public IActionResult Go(User user, string passconf)
 {
     if (user.Password != passconf)
     {
         HttpContext.Session.SetString("ErrorMessage", "Passwords don't match");
         return(RedirectToAction("Index", "Register"));
     }
     try
     {
         DatabaseOperations.AddUser(user.Login, user.Password);
     }
     catch (Exception ex)
     {
         if (ex is DatabaseException)
         {
             HttpContext.Session.SetString("ErrorMessage", ex.Message);
             return(RedirectToAction("Index", "Register"));
         }
     }
     if (HttpContext.Session.Keys.Contains("ErrorMessage"))
     {
         HttpContext.Session.Remove("ErrorMessage");
     }
     HttpContext.Session.SetString("LI", "true");
     HttpContext.Session.SetString("User", user.Login);
     return(RedirectToAction("MailboxCreate", "Mailbox"));
 }