Insert data into Database using Entity Framework in ASP.Net MVC

hi

I create MVC project and want to insert data into database I use EntityFrameworks

but here when I run page and fill textboxs and click button to inserting data into database it doesnt insert data into database it didnt make any error but didn't insert data into database

below are codes

controller 

        public ActionResult register(User user)
        {
            if (ModelState.IsValid == true)
            {

                //stud.BirthDate = stud.BirthDate.Value.ToMiladi();
                if (bl.Add(user) == true)
                {
                    ViewBag.Message = "ثبت شد";
                    ViewBag.Style = "lightgreen";
                }
                else
                {
                    ViewBag.Message = "ثبت نشد";
                    ViewBag.Style = "palevioletred";
                }
            }
            else
            {
                ViewBag.Message = "مقادیر را بدرستی وارد کنید";
                ViewBag.Style = "palevioletred";
            }
            return View();
        }

and UserRepository.cs

        MvcShopDbEntities db = new MvcShopDbEntities();
        public bool Add(User user)
        {
            try
            {
                db.Users.Add(user);
                return Convert.ToBoolean(db.SaveChanges());
            }
            catch (Exception)
            {
                return false;
            }
        }

I debugged it and took video

please see below video

https://vimeo.com/328467983 

where is my mistake?

Best regards

neda