Added Site Setting to change locale.

app/controllers/application_controller.rb

@@ -21,6 +21,7 @@ class ApplicationController < ActionController::Base
   before_filter :store_incoming_links
   before_filter :preload_json
   before_filter :check_xhr
+  before_filter :set_locale
 
   rescue_from Exception do |exception|
     unless [ ActiveRecord::RecordNotFound, ActionController::RoutingError,
@@ -77,6 +78,11 @@ class ApplicationController < ActionController::Base
     render file: 'public/403', formats: [:html], layout: false, status: 403
   end
 
+
+  def set_locale
+    I18n.locale = SiteSetting.default_locale
+  end
+
   def store_preloaded(key, json)
     @preloaded ||= {}
     # I dislike that there is a gsub as opposed to a gsub!