Create role appointments only after persisting roles
Create role appointments only after persisting roles

When a RoleAppointment is added to a Role, the RoleAppointment resets
its Role association. We can avoid this by using an `after :create`
hook, which runs after persisting, rather than `after :build`, which
runs before, in the role factories.

alphagov/whitehall,alphagov/whitehall,alphagov/whitehall,alphagov/whitehall