public ActionResult <Subscribe> Create([FromHeaderAttribute] string Authorization, Subscribe subscribe)
        {
            if (isAuthorized(Authorization))
            {
                User   user    = _usersService.Get(subscribe.ID_User);
                Course course  = _courseService.Get(subscribe.ID_Course);
                string message = "Te-ai abonat la cursul: " + course.Title;
                MailHelper.SendMail(user.Email, message);

                _subscribeService.Create(subscribe);
                return(CreatedAtRoute("GetSubscribe", new { id = subscribe._id.ToString() }, subscribe));
            }
            else
            {
                return(Unauthorized());
            }
        }