Don't use magic finders on Classifications

The friendly_id magic find override module doesn't play nice with Rails STI,
which is a problem for Topics and TopicalEvents. For these models, use the new
recommended method of finding instances based on their slug, which is to go via
the `friendly` scope.

Eventually, all code should be updated to use this instead of the magic find
override module as it isn't very stable and keeps breaking with new releases of
Rails[1]. Doing this is before the upgrade to Rails 4 is complete is going to be
hard however, so deferring until later.

[1] norman/friendly_id#607

app/controllers/admin/about_pages_controller.rb

@@ -39,7 +39,7 @@ def human_friendly_model_name
 
 private
   def find_topical_event
-    @topical_event = TopicalEvent.find(params[:topical_event_id])
+    @topical_event = TopicalEvent.friendly.find(params[:topical_event_id])
   end
 
   def find_page

app/controllers/admin/classifications_controller.rb

@@ -24,7 +24,7 @@ def edit
   end
 
   def update
-    @classification = model_class.find(params[:id])
+    @classification = model_class.friendly.find(params[:id])
     if @classification.update_attributes(object_params)
       redirect_to [:admin, @classification], notice: "#{human_friendly_model_name} updated"
     else
@@ -33,7 +33,7 @@ def update
   end
 
   def destroy
-    @classification = model_class.find(params[:id])
+    @classification = model_class.friendly.find(params[:id])
     @classification.delete!
     if @classification.deleted?
       redirect_to [:admin, model_class], notice: "#{human_friendly_model_name} destroyed"
@@ -51,7 +51,7 @@ def build_object
   end
 
   def load_object
-    @classification = model_class.find(params[:id])
+    @classification = model_class.friendly.find(params[:id])
   end
 
   def model_name

app/controllers/admin/offsite_links_controller.rb

@@ -43,8 +43,8 @@ def show
   def load_parent
     @parent = WorldLocation.find(params[:world_location_id]) if params[:world_location_id]
     @parent = Organisation.find(params[:organisation_id]) if params[:organisation_id]
-    @parent = Topic.find(params[:topic_id]) if params[:topic_id]
-    @parent = TopicalEvent.find(params[:topical_event_id]) if params[:topical_event_id]
+    @parent = Topic.friendly.find(params[:topic_id]) if params[:topic_id]
+    @parent = TopicalEvent.friendly.find(params[:topical_event_id]) if params[:topical_event_id]
   end
 
   def load_offsite_link

app/controllers/admin/topical_events_controller.rb

@@ -3,12 +3,12 @@ class Admin::TopicalEventsController < Admin::ClassificationsController
   before_filter :destroy_blank_social_media_accounts, only: [:create, :update]
 
   def update
-    @classification = model_class.find(params[:id])
+    @classification = TopicalEvent.friendly.find(params[:id])
     if @classification.update_attributes(object_params)
       if object_params[:classification_featurings_attributes]
         redirect_to [:admin, @classification, :classification_featurings], notice: "Order of featured items updated"
       else
-        redirect_to [:admin, model_class.new], notice: "#{human_friendly_model_name} updated"
+        redirect_to [:admin, TopicalEvent.new], notice: "#{human_friendly_model_name} updated"
       end
     else
       render action: "edit"

app/controllers/topical_events_controller.rb

@@ -6,7 +6,7 @@ def index
   end
 
   def show
-    @classification = TopicalEvent.find(params[:id])
+    @classification = TopicalEvent.friendly.find(params[:id])
     @policies = @classification.published_policies.includes(:translations, :document)
     @publications = fetch_associated(:published_publications, PublicationesquePresenter)
     @consultations = fetch_associated(:published_consultations, PublicationesquePresenter)

app/controllers/topics_controller.rb

@@ -2,7 +2,7 @@ class TopicsController < ClassificationsController
   enable_request_formats show: :atom
 
   def show
-    @classification = Topic.find(params[:id])
+    @classification = Topic.friendly.find(params[:id])
 
     respond_to do |format|
       format.html do

db/data_migration/20141015122422_ebola_response_slug_change.rb

@@ -1,4 +1,4 @@
-ebola_response = TopicalEvent.find('ebola-government-response')
+ebola_response = TopicalEvent.friendly.find('ebola-government-response')
 
 old_url = ebola_response.search_link
 ebola_response.remove_from_search_index