fixes #862

app/models/post.rb

@@ -740,6 +740,8 @@ class Post < ActiveRecord::Base
         parent.add_favorite!(User.find(user_id))
         remove_favorite!(User.find(user_id))
       end
+
+      update_column(:score, 0)
     end
   end
   

test/unit/post_test.rb

@@ -137,6 +137,7 @@ class PostTest < ActiveSupport::TestCase
           p1.reload
           assert(!Favorite.exists?(:post_id => c1.id, :user_id => user.id))
           assert(Favorite.exists?(:post_id => p1.id, :user_id => user.id))
+          assert_equal(0, c1.score)
         end
 
         should "update the parent's has_children flag" do