Lots of our controllers (and views, but we'll get to those later) contain business logic. A big task will be to move that to models and concerns.
This is related to #48, moving authorization logic into Authorizer classes.
I intend to tackle these controller-by-controller:
Use new Signup model in AccountsController [#40]
I'm going to close this ticket for now. Tackling all this in a single go isn't reasonable :(
I will instead open a few tickets to refactor the most offensive controllers.