The nixOS test failed sporadically with a timeout.
This is due to a race condition in the startup of
the scheduler vs the task-queue.
The scheduler runs the migration scripts in "pre-start" and
celery isn't available, yet. The celery worker (paperless-task-queue)
was already started by systemd but was unable to connect
(as the migration scripts from "pre-start" still ran).
This fix adds the necessary "after" condition in the systemd
worker unit and adds a test to "paperless"
Signed-off-by: Florian Brandes <florian.brandes@posteo.de>
The paperless project has moved on to paperless-ng and the original
paperless package in Nixpkgs has stopped working recently (due to
version incompatibility with the providede Django package).
Instead of investing more time into the old module we should migrate all
users to the new module instead.
