Added a condition to CheckAllowedMixin to see if check_allowed returns a bool
Added a condition to CheckAllowedMixin to see if check_allowed returns a bool

Since functions return None by default, it's pretty easy to forget to
add a "return True" to the end of the callback and wonder why you keep
getting 404'd

michaelwisely/django-competition,michaelwisely/django-competition,michaelwisely/django-competition