new_contents: from django.db.models import Manager
  from django.db.models.query_utils import Q
  
  class PermissionManager(Manager):
  
      def for_user(self, user=None):
          if user and user.is_authenticated():
              return self.get_query_set().filter(Q(group=None) | Q(group__user=user))
          else:
              return self.get_query_set().filter(group=None)
  
subject: Add new PermissionsManager that will be used by most Samklang modules