diff --git a/Gemfile b/Gemfile
index a8c24df..595c5f2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,7 +2,7 @@ source 'https://rubygems.org'
 
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
-gem 'rails', '6.0.3.4'
+gem 'rails', '6.1.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3', '~> 1.4.1'
 
@@ -35,6 +35,7 @@ gem 'jbuilder', '~> 2.10.1'
 gem 'sdoc', '~> 2.0.3',          group: :doc
 
 gem 'web-console', '~> 4.1.0', group: :development
+gem 'listen', '~> 3.1.5', group: :development
 
 # Use Codacy for coverage
 gem 'codacy-coverage', :require => false
diff --git a/Gemfile.lock b/Gemfile.lock
index 2a0223d..a16df44 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,61 +1,65 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    actioncable (6.0.3.4)
-      actionpack (= 6.0.3.4)
+    actioncable (6.1.1)
+      actionpack (= 6.1.1)
+      activesupport (= 6.1.1)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
-    actionmailbox (6.0.3.4)
-      actionpack (= 6.0.3.4)
-      activejob (= 6.0.3.4)
-      activerecord (= 6.0.3.4)
-      activestorage (= 6.0.3.4)
-      activesupport (= 6.0.3.4)
+    actionmailbox (6.1.1)
+      actionpack (= 6.1.1)
+      activejob (= 6.1.1)
+      activerecord (= 6.1.1)
+      activestorage (= 6.1.1)
+      activesupport (= 6.1.1)
       mail (>= 2.7.1)
-    actionmailer (6.0.3.4)
-      actionpack (= 6.0.3.4)
-      actionview (= 6.0.3.4)
-      activejob (= 6.0.3.4)
+    actionmailer (6.1.1)
+      actionpack (= 6.1.1)
+      actionview (= 6.1.1)
+      activejob (= 6.1.1)
+      activesupport (= 6.1.1)
       mail (~> 2.5, >= 2.5.4)
       rails-dom-testing (~> 2.0)
-    actionpack (6.0.3.4)
-      actionview (= 6.0.3.4)
-      activesupport (= 6.0.3.4)
-      rack (~> 2.0, >= 2.0.8)
+    actionpack (6.1.1)
+      actionview (= 6.1.1)
+      activesupport (= 6.1.1)
+      rack (~> 2.0, >= 2.0.9)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.2.0)
-    actiontext (6.0.3.4)
-      actionpack (= 6.0.3.4)
-      activerecord (= 6.0.3.4)
-      activestorage (= 6.0.3.4)
-      activesupport (= 6.0.3.4)
+    actiontext (6.1.1)
+      actionpack (= 6.1.1)
+      activerecord (= 6.1.1)
+      activestorage (= 6.1.1)
+      activesupport (= 6.1.1)
       nokogiri (>= 1.8.5)
-    actionview (6.0.3.4)
-      activesupport (= 6.0.3.4)
+    actionview (6.1.1)
+      activesupport (= 6.1.1)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.1, >= 1.2.0)
-    activejob (6.0.3.4)
-      activesupport (= 6.0.3.4)
+    activejob (6.1.1)
+      activesupport (= 6.1.1)
       globalid (>= 0.3.6)
-    activemodel (6.0.3.4)
-      activesupport (= 6.0.3.4)
-    activerecord (6.0.3.4)
-      activemodel (= 6.0.3.4)
-      activesupport (= 6.0.3.4)
-    activestorage (6.0.3.4)
-      actionpack (= 6.0.3.4)
-      activejob (= 6.0.3.4)
-      activerecord (= 6.0.3.4)
+    activemodel (6.1.1)
+      activesupport (= 6.1.1)
+    activerecord (6.1.1)
+      activemodel (= 6.1.1)
+      activesupport (= 6.1.1)
+    activestorage (6.1.1)
+      actionpack (= 6.1.1)
+      activejob (= 6.1.1)
+      activerecord (= 6.1.1)
+      activesupport (= 6.1.1)
       marcel (~> 0.3.1)
-    activesupport (6.0.3.4)
+      mimemagic (~> 0.3.2)
+    activesupport (6.1.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
-      i18n (>= 0.7, < 2)
-      minitest (~> 5.1)
-      tzinfo (~> 1.1)
-      zeitwerk (~> 2.2, >= 2.2.2)
+      i18n (>= 1.6, < 2)
+      minitest (>= 5.1)
+      tzinfo (~> 2.0)
+      zeitwerk (~> 2.3)
     addressable (2.7.0)
       public_suffix (>= 2.0.2, < 5.0)
     autoprefixer-rails (10.0.2.0)
@@ -93,7 +97,7 @@ GEM
     diff-lcs (1.4.4)
     diffy (3.4.0)
     docile (1.3.2)
-    erubi (1.9.0)
+    erubi (1.10.0)
     execjs (2.7.0)
     faraday (1.0.0)
       multipart-post (>= 1.2, < 3)
@@ -104,7 +108,7 @@ GEM
       activesupport (>= 4.2.0)
     hashdiff (1.0.1)
     hashie (4.1.0)
-    i18n (1.8.5)
+    i18n (1.8.7)
       concurrent-ruby (~> 1.0)
     jbuilder (2.10.1)
       activesupport (>= 5.0.0)
@@ -113,7 +117,11 @@ GEM
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
     jwt (2.2.1)
-    loofah (2.7.0)
+    listen (3.1.5)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+      ruby_dep (~> 1.2)
+    loofah (2.8.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.1)
@@ -124,7 +132,7 @@ GEM
     mimemagic (0.3.5)
     mini_mime (1.0.2)
     mini_portile2 (2.5.0)
-    minitest (5.14.2)
+    minitest (5.14.3)
     msgpack (1.3.3)
     multi_json (1.14.1)
     multi_xml (0.6.0)
@@ -156,20 +164,20 @@ GEM
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
-    rails (6.0.3.4)
-      actioncable (= 6.0.3.4)
-      actionmailbox (= 6.0.3.4)
-      actionmailer (= 6.0.3.4)
-      actionpack (= 6.0.3.4)
-      actiontext (= 6.0.3.4)
-      actionview (= 6.0.3.4)
-      activejob (= 6.0.3.4)
-      activemodel (= 6.0.3.4)
-      activerecord (= 6.0.3.4)
-      activestorage (= 6.0.3.4)
-      activesupport (= 6.0.3.4)
-      bundler (>= 1.3.0)
-      railties (= 6.0.3.4)
+    rails (6.1.1)
+      actioncable (= 6.1.1)
+      actionmailbox (= 6.1.1)
+      actionmailer (= 6.1.1)
+      actionpack (= 6.1.1)
+      actiontext (= 6.1.1)
+      actionview (= 6.1.1)
+      activejob (= 6.1.1)
+      activemodel (= 6.1.1)
+      activerecord (= 6.1.1)
+      activestorage (= 6.1.1)
+      activesupport (= 6.1.1)
+      bundler (>= 1.15.0)
+      railties (= 6.1.1)
       sprockets-rails (>= 2.0.0)
     rails-controller-testing (1.0.5)
       actionpack (>= 5.0.1.rc1)
@@ -183,17 +191,21 @@ GEM
     rails-i18n (6.0.0)
       i18n (>= 0.7, < 2)
       railties (>= 6.0.0, < 7)
-    railties (6.0.3.4)
-      actionpack (= 6.0.3.4)
-      activesupport (= 6.0.3.4)
+    railties (6.1.1)
+      actionpack (= 6.1.1)
+      activesupport (= 6.1.1)
       method_source
       rake (>= 0.8.7)
-      thor (>= 0.20.3, < 2.0)
-    rake (13.0.1)
+      thor (~> 1.0)
+    rake (13.0.3)
+    rb-fsevent (0.10.4)
+    rb-inotify (0.10.1)
+      ffi (~> 1.0)
     rdoc (6.2.1)
     responders (3.0.1)
       actionpack (>= 5.0)
       railties (>= 5.0)
+    ruby_dep (1.5.0)
     sassc (2.4.0)
       ffi (~> 1.9)
     sassc-rails (2.1.2)
@@ -217,13 +229,12 @@ GEM
       sprockets (>= 3.0.0)
     sqlite3 (1.4.2)
     thor (1.0.1)
-    thread_safe (0.3.6)
     tilt (2.0.10)
     turbolinks (5.2.1)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
-    tzinfo (1.2.8)
-      thread_safe (~> 0.1)
+    tzinfo (2.0.4)
+      concurrent-ruby (~> 1.0)
     uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)
     warden (1.2.9)
@@ -243,7 +254,7 @@ GEM
     will_paginate (3.3.0)
     will_paginate-bootstrap4 (0.2.2)
       will_paginate (~> 3.0, >= 3.0.0)
-    zeitwerk (2.4.1)
+    zeitwerk (2.4.2)
 
 PLATFORMS
   ruby
@@ -260,10 +271,11 @@ DEPENDENCIES
   font-awesome-sass (~> 5.15.1)
   jbuilder (~> 2.10.1)
   jquery-rails (~> 4.4.0)
+  listen (~> 3.1.5)
   mysql2 (~> 0.5.2)
   omniauth
   omniauth-github
-  rails (= 6.0.3.4)
+  rails (= 6.1.1)
   rails-controller-testing
   rails-i18n (~> 6.0.0)
   sassc-rails (~> 2.1.2)
diff --git a/bin/rails b/bin/rails
index 0739660..6fb4e40 100755
--- a/bin/rails
+++ b/bin/rails
@@ -1,4 +1,4 @@
 #!/usr/bin/env ruby
 APP_PATH = File.expand_path('../config/application', __dir__)
-require_relative '../config/boot'
-require 'rails/commands'
+require_relative "../config/boot"
+require "rails/commands"
diff --git a/bin/rake b/bin/rake
index 1724048..4fbf10b 100755
--- a/bin/rake
+++ b/bin/rake
@@ -1,4 +1,4 @@
 #!/usr/bin/env ruby
-require_relative '../config/boot'
-require 'rake'
+require_relative "../config/boot"
+require "rake"
 Rake.application.run
diff --git a/bin/setup b/bin/setup
index 5853b5e..583be4a 100755
--- a/bin/setup
+++ b/bin/setup
@@ -1,5 +1,5 @@
 #!/usr/bin/env ruby
-require 'fileutils'
+require "fileutils"
 
 # path to your application root.
 APP_ROOT = File.expand_path('..', __dir__)
@@ -9,8 +9,8 @@ def system!(*args)
 end
 
 FileUtils.chdir APP_ROOT do
-  # This script is a way to setup or update your development environment automatically.
-  # This script is idempotent, so that you can run it at anytime and get an expectable outcome.
+  # This script is a way to set up or update your development environment automatically.
+  # This script is idempotent, so that you can run it at any time and get an expectable outcome.
   # Add necessary setup steps to this file.
 
   puts '== Installing dependencies =='
@@ -18,7 +18,7 @@ FileUtils.chdir APP_ROOT do
   system('bundle check') || system!('bundle install')
 
   # Install JavaScript dependencies
-  # system('bin/yarn')
+  # system! 'bin/yarn'
 
   # puts "\n== Copying sample files =="
   # unless File.exist?('config/database.yml')
diff --git a/bin/yarn b/bin/yarn
index 460dd56..4700a9e 100755
--- a/bin/yarn
+++ b/bin/yarn
@@ -1,9 +1,15 @@
 #!/usr/bin/env ruby
 APP_ROOT = File.expand_path('..', __dir__)
 Dir.chdir(APP_ROOT) do
-  begin
-    exec "yarnpkg", *ARGV
-  rescue Errno::ENOENT
+  yarn = ENV["PATH"].split(File::PATH_SEPARATOR).
+    select { |dir| File.expand_path(dir) != __dir__ }.
+    product(["yarn", "yarn.exe"]).
+    map { |dir, file| File.expand_path(file, dir) }.
+    find { |file| File.executable?(file) }
+
+  if yarn
+    exec yarn, *ARGV
+  else
     $stderr.puts "Yarn executable was not detected in the system."
     $stderr.puts "Download Yarn at https://yarnpkg.com/en/docs/install"
     exit 1
diff --git a/config.ru b/config.ru
index 5bc2a61..4a3c09a 100644
--- a/config.ru
+++ b/config.ru
@@ -1,4 +1,6 @@
 # This file is used by Rack-based servers to start the application.
 
-require ::File.expand_path('../config/environment',  __FILE__)
+require_relative "config/environment"
+
 run Rails.application
+Rails.application.load_server
diff --git a/config/application.rb b/config/application.rb
index 2925aed..cc760a8 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -1,6 +1,6 @@
-require_relative 'boot'
+require_relative "boot"
 
-require 'rails/all'
+require "rails/all"
 
 # Require the gems listed in Gemfile, including any gems
 # you've limited to :test, :development, or :production.
@@ -9,12 +9,12 @@ Bundler.require(*Rails.groups)
 module Projekteuler
   class Application < Rails::Application
     # Initialize configuration defaults for originally generated Rails version.
-    config.load_defaults 6.0
+    config.load_defaults 6.1
 
-    # Settings in config/environments/* take precedence over those specified here.
-    # Application configuration can go into files in config/initializers
-    # -- all .rb files in that directory are automatically loaded after loading
-    # the framework and any gems in your application.
+    # Configuration for the application, engines, and railties goes here.
+    #
+    # These settings can be overridden in specific environments using the files
+    # in config/environments, which are processed later.
 
     config.action_dispatch.default_headers = {
         'X-Frame-Options' => 'DENY',
diff --git a/config/boot.rb b/config/boot.rb
index b9e460c..3cda23b 100644
--- a/config/boot.rb
+++ b/config/boot.rb
@@ -1,4 +1,4 @@
 ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __dir__)
 
-require 'bundler/setup' # Set up gems listed in the Gemfile.
-require 'bootsnap/setup' # Speed up boot time by caching expensive operations.
+require "bundler/setup" # Set up gems listed in the Gemfile.
+require "bootsnap/setup" # Speed up boot time by caching expensive operations.
diff --git a/config/environment.rb b/config/environment.rb
index 426333b..cac5315 100644
--- a/config/environment.rb
+++ b/config/environment.rb
@@ -1,5 +1,5 @@
 # Load the Rails application.
-require_relative 'application'
+require_relative "application"
 
 # Initialize the Rails application.
 Rails.application.initialize!
diff --git a/config/environments/development.rb b/config/environments/development.rb
index e13616e..efc473b 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -1,8 +1,10 @@
+require "active_support/core_ext/integer/time"
+
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
-  # In the development environment your application's code is reloaded on
-  # every request. This slows down response time but is perfect for development
+  # In the development environment your application's code is reloaded any time
+  # it changes. This slows down response time but is perfect for development
   # since you don't have to restart the web server when you make code changes.
   config.cache_classes = false
 
@@ -39,6 +41,12 @@ Rails.application.configure do
   # Print deprecation notices to the Rails logger.
   config.active_support.deprecation = :log
 
+  # Raise exceptions for disallowed deprecations.
+  config.active_support.disallowed_deprecation = :raise
+
+  # Tell Active Support which deprecation messages to disallow.
+  config.active_support.disallowed_deprecation_warnings = []
+
   # Raise an error on page load if there are pending migrations.
   config.active_record.migration_error = :page_load
 
@@ -54,9 +62,15 @@ Rails.application.configure do
   config.assets.quiet = true
 
   # Raises error for missing translations.
-  config.action_view.raise_on_missing_translations = true
+  config.i18n.raise_on_missing_translations = true
+
+  # Annotate rendered view with file names.
+  # config.action_view.annotate_rendered_view_with_filenames = true
 
   # Use an evented file watcher to asynchronously detect changes in source code,
   # routes, locales, etc. This feature depends on the listen gem.
-  # config.file_watcher = ActiveSupport::EventedFileUpdateChecker
+  config.file_watcher = ActiveSupport::EventedFileUpdateChecker
+
+  # Uncomment if you wish to allow Action Cable access from any origin.
+  # config.action_cable.disable_request_forgery_protection = true
 end
diff --git a/config/environments/production.rb b/config/environments/production.rb
index 1a5b5e2..4bb0a36 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -1,3 +1,5 @@
+require "active_support/core_ext/integer/time"
+
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
@@ -32,7 +34,7 @@ Rails.application.configure do
   config.assets.compile = false
 
   # Enable serving of images, stylesheets, and JavaScripts from an asset server.
-  # config.action_controller.asset_host = 'http://assets.example.com'
+  # config.asset_host = 'http://assets.example.com'
 
   # Specifies the header that your server uses for sending files.
   # config.action_dispatch.x_sendfile_header = 'X-Sendfile' # for Apache
@@ -49,9 +51,9 @@ Rails.application.configure do
   # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
   config.force_ssl = true
 
-  # Use the lowest log level to ensure availability of diagnostic information
-  # when problems arise.
-  config.log_level = :debug
+  # Include generic and useful information about system operation, but avoid logging too much
+  # information to avoid inadvertent exposure of personally identifiable information (PII).
+  config.log_level = :info
 
   # Prepend all log lines with the following tags.
   config.log_tags = [ :request_id ]
@@ -71,16 +73,22 @@ Rails.application.configure do
 
   # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
   # the I18n.default_locale when a translation cannot be found).
-  config.i18n.fallbacks = [I18n.default_locale]
+  config.i18n.fallbacks = true
 
   # Send deprecation notices to registered listeners.
   config.active_support.deprecation = :notify
 
+  # Log disallowed deprecations.
+  config.active_support.disallowed_deprecation = :log
+
+  # Tell Active Support which deprecation messages to disallow.
+  config.active_support.disallowed_deprecation_warnings = []
+
   # Use default logging formatter so that PID and timestamp are not suppressed.
   config.log_formatter = ::Logger::Formatter.new
 
   # Use a different logger for distributed setups.
-  # require 'syslog/logger'
+  # require "syslog/logger"
   # config.logger = ActiveSupport::TaggedLogging.new(Syslog::Logger.new 'app-name')
 
   if ENV["RAILS_LOG_TO_STDOUT"].present?
diff --git a/config/environments/test.rb b/config/environments/test.rb
index b4edb9c..fd9cd12 100644
--- a/config/environments/test.rb
+++ b/config/environments/test.rb
@@ -5,7 +5,7 @@
 
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
-  
+
   config.cache_classes = true
 
   # Do not eager load code on boot. This avoids loading your whole application
@@ -43,6 +43,15 @@ Rails.application.configure do
   # Print deprecation notices to the stderr.
   config.active_support.deprecation = :stderr
 
+  # Raise exceptions for disallowed deprecations.
+  config.active_support.disallowed_deprecation = :raise
+
+  # Tell Active Support which deprecation messages to disallow.
+  config.active_support.disallowed_deprecation_warnings = []
+
   # Raises error for missing translations.
-  config.action_view.raise_on_missing_translations = true
+  config.i18n.raise_on_missing_translations = true
+
+  # Annotate rendered view with file names.
+  # config.action_view.annotate_rendered_view_with_filenames = true
 end
diff --git a/config/initializers/assets.rb b/config/initializers/assets.rb
index 719bc58..4b828e8 100644
--- a/config/initializers/assets.rb
+++ b/config/initializers/assets.rb
@@ -7,3 +7,8 @@ Rails.application.config.assets.version = '1.0'
 # Rails.application.config.assets.paths << Emoji.images_path
 # Add Yarn node_modules folder to the asset load path.
 Rails.application.config.assets.paths << Rails.root.join('node_modules')
+
+# Precompile additional assets.
+# application.js, application.css, and all non-JS/CSS in the app/assets
+# folder are already added.
+# Rails.application.config.assets.precompile += %w( admin.js admin.css )
diff --git a/config/initializers/backtrace_silencers.rb b/config/initializers/backtrace_silencers.rb
index 59385cd..33699c3 100644
--- a/config/initializers/backtrace_silencers.rb
+++ b/config/initializers/backtrace_silencers.rb
@@ -1,7 +1,8 @@
 # Be sure to restart your server when you modify this file.
 
 # You can add backtrace silencers for libraries that you're using but don't wish to see in your backtraces.
-# Rails.backtrace_cleaner.add_silencer { |line| line =~ /my_noisy_library/ }
+# Rails.backtrace_cleaner.add_silencer { |line| /my_noisy_library/.match?(line) }
 
-# You can also remove all the silencers if you're trying to debug a problem that might stem from framework code.
-# Rails.backtrace_cleaner.remove_silencers!
+# You can also remove all the silencers if you're trying to debug a problem that might stem from framework code
+# by setting BACKTRACE=1 before calling your invocation, like "BACKTRACE=1 ./bin/rails runner 'MyClass.perform'".
+Rails.backtrace_cleaner.remove_silencers! if ENV["BACKTRACE"]
diff --git a/config/initializers/filter_parameter_logging.rb b/config/initializers/filter_parameter_logging.rb
index 4a994e1..4b34a03 100644
--- a/config/initializers/filter_parameter_logging.rb
+++ b/config/initializers/filter_parameter_logging.rb
@@ -1,4 +1,6 @@
 # Be sure to restart your server when you modify this file.
 
 # Configure sensitive parameters which will be filtered from the log file.
-Rails.application.config.filter_parameters += [:password]
+Rails.application.config.filter_parameters += [
+  :passw, :secret, :token, :_key, :crypt, :salt, :certificate, :otp, :ssn
+]
diff --git a/config/initializers/permissions_policy.rb b/config/initializers/permissions_policy.rb
new file mode 100644
index 0000000..b2be4a2
--- /dev/null
+++ b/config/initializers/permissions_policy.rb
@@ -0,0 +1,11 @@
+# Define an application-wide HTTP permissions policy. For further
+# information see https://developers.google.com/web/updates/2018/06/feature-policy
+#
+Rails.application.config.permissions_policy do |f|
+  f.camera      :none
+  f.gyroscope   :none
+  f.microphone  :none
+  f.usb         :none
+  f.fullscreen  :self
+  f.payment     :none
+end