Fix Group Rating sort not working; Fixes #374

Fixes https://github.com/OpenUserJs/OpenUserJS.org/issues/374

I can confirm that this fix is making sorting working on dev with global dev db.
I can't test it on the live db where it also contains [weird values](https://github.com/OpenUserJs/OpenUserJS.org/issues/374). It makes sense that this will fix that issue too.