Timeout during "Passed previous semester"

[tworide]

No description provided.

[espenak]

This is most likely caused by email sending for each new feedback created.

A usable and simple solution for now

We can work around this, and improve the scalability of Devilry with https://pypi.python.org/pypi/django-celery-email. Celery is already intergrated with devilry-deploy, so we just need to add the package.

The permannent solution

A more robust and permannent solution will come with #471. Then all messages will be sent to the notification system, and a Celery task will handle sending, re-sending (in case of errors), etc.