Technical 500 by group membership
Based loosely on [Eric's middleware](http://ericholscher.com/blog/2009/sep/5/debugging-django-production-revisited/), this middleware will show the technical 500 page (which you'd get if DEBUG == True) to any user who is (1) superuser and (2) a member of the settings.TECHNICAL_500_GROUP_NAME group. (If no setting exists, 'Technical Errors' is the presumed group name. I agreed with the comments that caching should be unnecessary given the (presumptive) edge case of exception + superuser. Assuming you don't have tons of superusers, this code is a good bit simpler.
- admin
- user
- auth
- debugging
- 500