'Update a user given its id'

@requires_auth
@can_access_account
@api.doc('update_user', responses=PUT_RESPONSES)
@api.marshal_with(USER)
@api.expect(USER_PUT)
def put(self, user_id):

    user = DAO.update(user_id, self.api.payload)
    record_activity('update_user', user=user)
    return user
