add the message on failed request to the db as a celery task

[kencochrane]

creating a new issue for this, breaking it out from #85 so it is easier to track.

It would be nice if we had an option to add the message on failed request to the db as a celery task. This would be helpful for people who are already using celery.

I don't want to make celery a requirement, so it should be something that is configurable. If they have celery enabled, then we will use celery, if not, we will do what we do today, and hit the database directly.

/cc @MattBlack85