refactored favorites

app/models/post.rb

@@ -525,11 +525,7 @@ class Post < ActiveRecord::Base
     end
 
     def add_favorite!(user)
-      return if favorited_by?(user.id)
-      append_user_to_fav_string(user.id)
-      Post.connection.execute_sql("update posts set fav_count = fav_count + 1 where id = #{id}")
-      Post.connection.execute_sql("update posts set score = score + 1 where id = #{id}") if CurrentUser.is_privileged?
-      user.add_favorite!(self)
+      Favorite.add(self, user)
     end
 
     def delete_user_from_fav_string(user_id)
@@ -537,11 +533,7 @@ class Post < ActiveRecord::Base
     end
 
     def remove_favorite!(user)
-      return unless favorited_by?(user.id)
-      Post.connection.execute_sql("update posts set fav_count = fav_count - 1 where id = #{id}")
-      Post.connection.execute_sql("update posts set score = score - 1 where id = #{id}") if CurrentUser.is_privileged?
-      delete_user_from_fav_string(user.id)
-      user.remove_favorite!(self)
+      Favorite.remove(self, user)
     end
 
     def favorited_user_ids