More complete SqlEvent#cached? spec.
Spec name isn't aware of implementation of #cached?.
Isolate Form::SignIn spec.
Experiment with dependency injection in Forms::NewApp.
Switch from sidekiq delayed mailer extension to explicit mail worker.

A little less coupled to sidekiq and allows finer control over mail
queues, retries, etc.
Extract User.email_available? method.
Isolate SignUp form spec.