public ActionResult ShowMessage(string toUser, string messageContent)
        {
            if (messageContent.IsNullOrWhiteSpace())
            {
                return(RedirectToAction("ShowMessage"));
            }

            //Create new object of Message
            var newMessage = new Message
            {
                MessageContent    = messageContent,
                DateTimeOfMessage = DateTime.Now,
                FromUserName      = User.Identity.Name,
                ToUserName        = toUser
            };

            //Add new Message to database
            _repo.AddNewMessage(newMessage);
            //Save changes in database
            _repo.SaveChanges();


            var newMessageNotification = new Notification
            {
                NotificationTitle    = "Nowa wiadomość!",
                NotificationContent  = "Nowa wiadomość od: " + User.Identity.Name,
                NotificationDateTime = DateTime.Now,
                Message         = _repo.GetMessageById(newMessage.Id),
                ApplicationUser = _repo.GetUser(toUser)
            };

            _repo.AddNewNotification(newMessageNotification);
            //Save changes in database
            _repo.SaveChanges();

            return(RedirectToAction("ShowMessage", "Message", new { username = toUser }));
        }