@RequestMapping(value = "/registration", method = RequestMethod.POST)
  public String submit(
      @ModelAttribute("joinFormDTO") @Validated JoinFormDTO joinFormDTO,
      BindingResult bindingResult,
      RedirectAttributes attr,
      HttpServletResponse response)
      throws Exception {
    if (bindingResult.hasErrors()) {
      attr.addFlashAttribute(
          "org.springframework.validation.BindingResult.joinFormDTO", bindingResult);
      attr.addFlashAttribute("joinFormDTO", joinFormDTO);
      return "redirect:/registration";
    }

    // Ok, Let's sign up!
    userRepository.save(joinFormDTO.toUser());

    // Create token
    AuthenticationUtil.createToken(joinFormDTO.getUsername(), response);

    return "redirect:/joinsuccess";
  }