code: @Get("/users/me")
      public HttpResponse usersMe() throws Exception {
          final User user = AuthUtil.currentUser();
          return HttpResponse.of(HttpStatus.OK, MediaType.JSON_UTF_8,
                                 HttpData.of(Jackson.writeValueAsBytes(user)));
      }
docs: GET /users/me
  Returns a login {@link User} if the user is authorized. Otherwise, {@code 401 Unauthorized} HTTP
  response is sent.