Merge pull request #3082 from evazion/feat-data-is-fav

Add `data-is-favorited` attribute to post thumbnails.

app/models/post.rb

@@ -954,7 +954,7 @@ class Post < ActiveRecord::Base
     end
 
     def favorited_by?(user_id)
-      fav_string =~ /(?:\A| )fav:#{user_id}(?:\Z| )/
+      !!(fav_string =~ /(?:\A| )fav:#{user_id}(?:\Z| )/)
     end
 
     def append_user_to_fav_string(user_id)

app/presenters/post_presenter.rb

@@ -90,6 +90,7 @@ class PostPresenter < Presenter
       data-preview-file-url="#{post.preview_file_url}"
       data-source="#{h(post.source)}"
       data-normalized-source="#{h(post.normalized_source)}"
+      data-is-favorited="#{post.favorited_by?(CurrentUser.user.id)}"
     }.html_safe
   end