Make a generic record trait

[rien]

So we can have an ActiveRecord-like interface for our model structs.

Basic methods:

• An all, index method (with optional pagination parameters) to fetch all the records.
• A create method which INSERTs a new record in the database..
• An update method which UPDATEs an existing record.
• An destroy method which DELETEs an existing record.

Some of these methods have already been implemented in the User model, so this is will come down to abstracting that functionality.

A more difficult extension to this trait is tracking which fields of the record have been changed so we can UPDATE only changed fields. This seems cleaner, but would require a lot of bookkeeping.