Ohh ok, without this change all of our `scope`s were just immediately evaluating the argument and fetching _all_ such matching records immediately, instead of waiting to actually be called. This led to bugs like `pet_type.as_json` returning ALL pet states in the whole db, because the `PetState.emotion_order` scope was being treated as a single predefined query, rather than a query fragment to merge into the current context.
This also explains what happened in 724ed83: that's why things before the scope in the query were being ignored.
We were joining to the translations table to sort records
alphabetically, but then it sorted by *all* of the translations in
some strange way. Now use with_translations to restrict the join
to the current locale.
