Add config folder and example.py settings file
Update required version of APScheduler
Update requirements versions
Remove common app's Singleton model and use django-solo's SingletonModel instead
Move documents app api view back into their own module
More clear exception handling
Cleanups
Update HISTORY
Add anonymoususer sigleton model manager
Move tags app API view to their own module
Move sources app API views to their own module
Add missing import
Update release notes
Create the instance if it haven't already
PEP8 cleanup, unused imports, missing imports, style cleanups