diff --git a/Gemfile b/Gemfile
index 87908d9..15e21ab 100644
--- a/Gemfile
+++ b/Gemfile
@@ -34,7 +34,7 @@ gem 'turbolinks', '~> 5.2.1'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
 gem 'jbuilder', '~> 2.11.3'
 # bundle exec rake doc:rails generates the API under doc/api.
-gem 'sdoc', '~> 2.4.0',          group: :doc
+gem 'sdoc', '~> 2.6.1',          group: :doc
 
 gem 'web-console', '~> 4.2.0', group: :development
 gem 'listen', '~> 3.7.0', group: :development
diff --git a/Gemfile.lock b/Gemfile.lock
index d80cffa..0a70c33 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -201,7 +201,7 @@ GEM
       omniauth (~> 2.0)
     orm_adapter (0.5.0)
     popper_js (2.9.3)
-    psych (4.0.6)
+    psych (5.1.0)
       stringio
     public_suffix (4.0.6)
     puma (6.0.0)
@@ -249,7 +249,7 @@ GEM
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rdoc (6.4.0)
+    rdoc (6.5.0)
       psych (>= 4.0.0)
     responders (3.0.1)
       actionpack (>= 5.0)
@@ -264,7 +264,7 @@ GEM
       sprockets (> 3.0)
       sprockets-rails
       tilt
-    sdoc (2.4.0)
+    sdoc (2.6.1)
       rdoc (>= 5.0)
     sprockets (4.0.2)
       concurrent-ruby (~> 1.0)
@@ -275,7 +275,7 @@ GEM
       sprockets (>= 3.0.0)
     sqlite3 (1.6.2)
       mini_portile2 (~> 2.8.0)
-    stringio (3.0.5)
+    stringio (3.0.6)
     strscan (3.0.1)
     thor (1.2.1)
     tilt (2.0.10)
@@ -330,7 +330,7 @@ DEPENDENCIES
   rails-controller-testing
   rails-i18n (~> 7.0.6)
   sassc-rails (~> 2.1.2)
-  sdoc (~> 2.4.0)
+  sdoc (~> 2.6.1)
   sqlite3 (~> 1.6.2)
   turbolinks (~> 5.2.1)
   tzinfo-data