Relate user model by class string
Relate user model by class string

The class string is sufficient for creating the key relationship, and
under certain runtimes the import fails resulting in an
ImproperlyConfigured error on the model user class.

gh-11

aptivate/django-organizations,DESHRAJ/django-organizations,DESHRAJ/django-organizations,bennylope/django-organizations,aptivate/django-organizations,bennylope/django-organizations,GauthamGoli/django-organizations,aptivate/django-organizations,arteria/django-ar-organizations,GauthamGoli/django-organizations,st8st8/django-organizations,arteria/django-ar-organizations,st8st8/django-organizations