Add MathJax to seeds.rb, update locales

app/helpers/application_helper.rb

@@ -20,7 +20,7 @@ module ApplicationHelper
 
   # Returns the full title on a per-page basis.
   def full_title(page_title = '')
-    base_title = t('site_title')
+    base_title = t('application.site_title')
     if page_title.empty?
       base_title
     else

app/views/layouts/_header.html.erb

@@ -1,6 +1,6 @@
 <%= navbar position: :static do %>
     <%= vertical do %>
-        <%= link_to t(:site_title), root_path %>
+        <%= link_to t('application.site_title'), root_path %>
     <% end %>
     <%= horizontal do %>
         <%= nav class: 'navbar-left' do %>