Backends are their own model for user transparency and control. The priority and regex fields are used to automatically assign a Backend to make creating Embeds as easy as possible. However, it's hard to programmatically know if an assigned backend is the "best" backend, therefore the user has the final say.

A ChoiceField is a decent idea, but lacks flexibility of the Model implementation. The current Model allows the user to change the regex, priority and provide a description for the Backend—decisions we don't have to enforce on the user.