AT-AT needs to be able to track which user tasks failed and why. To
accomplish this we:
- Enabled Celery's results backend, which logs task results to a data
store; a Postgres table, in our case.
(https://docs.celeryproject.org/en/latest/userguide/tasks.html#result-backends)
- Created tables to track the relationships between the relevant models
(Environment, EnvironmentRole) and their task failures.
- Added an `on_failure` hook that tasks can use. The hook will add
records to the job failure tables.
Now a resource like an `Environment` has access to it task failures
through the corresponding failure table.
Notes:
- It might prove useful to use a real foreign key to the Celery results
table eventually. I did not do it here because it requires that we
explicitly store the Celery results table schema as a migration and
add a model for it. In the current implementation, AT-AT can be
agnostic about where the results live.
- We store the task results indefinitely, so it is important to specify
tasks for which we do not care about the results (like `send_mail`)
via the `ignore_result` kwarg.
We don't know for a fact that TO number uniqueness is a requirement at
the database level. For now, remove the unique constraint so that users
can enter redundant TOs.
Portfolio invitations do not associate a user entity until the
invitation has been accepted. User info, including DOD ID, is held on
the invitation itself. When a user accepts and invitation, their user
entry is associated with the corresponding `portfolio_role` entry.
The same change will be applied to `application_role` and application
invitations. For now, small changes have been made to
application-related methods so that that flow works as-is.
In the future, an `application_invitation1 will not refer to a `user` until
someone accepts the invitation; they'll only reference an
`application_role`. When a user is invited to an application, the
inviter can specify the environments the invitee should have access to.
For this to be possible, an `environment_role` should reference an
`application_role`, because no `user` entity will be known at that time.
In addition to updating all the models and domain methods necessary for
this change, this commit deletes unused code and tests that were
dependent on `environment_roles` having a `user_id` foreign key.
