@MessageMapping("/admin_removeUserByEmail")
  public void deleteUserByEmail(AdminMessage message) throws Exception {
    logger.info("Attempting to delete user " + message.getValue());
    User user = assertAdmin(message.getUserEmail(), message.getUserToken());

    userService.deleteUserByEmail(message.getValue());

    // tell the user that the game has been created
    messagingTemplate.convertAndSend(
        "/queue/" + user.getToken() + "/admin", "User " + message.getValue() + " has been removed");
  }