When trying to set a rival for a game/category in which you already have a rival, the button correctly says "Replace as a rival", but clicking it gives an error that "Category has already been taken", presumably because we're not removing the old rivalry before trying to create a new one.
When trying to set a rival for a game/category in which you already have a rival, the button correctly says "Replace as a rival", but clicking it gives an error that "Category has already been taken", presumably because we're not removing the old rivalry before trying to create a new one.