public async Task <IActionResult> Authenticate([Bind("Username")] User user)
        {
            User us = await LoginService.AuthenticationAsync(user);

            if (us != null)
            {
                UserSession session = new UserSession(user);
                HttpContext.Session.SetString("OpenSession", JsonConvert.SerializeObject(session));
                return(RedirectToAction("Hello"));
            }

            return(View());
        }