compatible with pymongo 1.9 and above
compatible with pymongo 1.9 and above

see http://api.mongodb.org/python/current/changelog.html#changes-in-version-1-9

fmoro/django-mongodbforms,lucidbard/django-mongodbforms,thomwiggers/django-mongodbforms,carlware/django-mongodbforms,jschrewe/django-mongodbforms