Merge branch '642-fwd-schoolapps-celery-task-aleksis-core-tasks-clear_oauth_tokens-fehlgeschlagen-ticket-751413' into 'master' Resolve "Fwd: [SchoolApps] Celery-Task aleksis.core.tasks.clear_oauth_tokens fehlgeschlagen! [Ticket#751413]" Closes #642 See merge request !950