FIX: Deprecation warnings on Rails with some topic queries

lib/topic_query.rb

@@ -224,6 +224,7 @@ class TopicQuery
 
       if @user
         result = result.joins("LEFT OUTER JOIN topic_users AS tu ON (topics.id = tu.topic_id AND tu.user_id = #{@user.id.to_i})")
+                       .references('tu')
       end
 
       category_id = nil
@@ -303,7 +304,7 @@ class TopicQuery
                          WHERE cu.user_id = ? AND
                                cu.category_id = topics.category_id AND
                                cu.notification_level = ?
-                         )", user.id, CategoryUser.notification_levels[:muted])
+                         )", user.id, CategoryUser.notification_levels[:muted]).references('cu')
       end
 
       list