Remove a user from an organization.

def destroy(self, request, pk=None, parent_lookup_organization=None):
        '''Remove a user from an organization.'''
        user = get_object_or_404(User, pk=pk)
        org = get_object_or_404(
            SeedOrganization, pk=parent_lookup_organization)
        self.check_object_permissions(request, org)
        org.users.remove(user)
        return Response(status=status.HTTP_204_NO_CONTENT)