I need to implement user rights for user groups (pretty similar to facebook groups). For example, each group can have members with rights like: can_post, can_delete, can_ban
Django has a built in groups system. Whenever you have a question like this, I recommend searching the Django docs, which are extensive, helpful, and well written.
So long as you are using the django.contrib.auth
app, you have access to groups. You can then assign permissions to those groups.
from django.contrib.auth.models import User, Group, Permission
from django.contrib.contenttypes.models import ContentType
content_type = ContentType.objects.get(app_label='myapp', model='BlogPost')
permission = Permission.objects.create(codename='can_publish',
name='Can Publish Posts',
content_type=content_type)
user = User.objects.get(username='duke_nukem')
group = Group.objects.get(name='wizard')
group.permissions.add(permission)
user.groups.add(group)