public ActionResult Registration(Models.UserModel user)
        {
            if (ModelState.IsValid)
            {
                using (var db = new MainDbEntitiesContext())
                {
                    var crypto = new SimpleCrypto.PBKDF2();

                    var encrpPass = crypto.Compute(user.password);

                    var sysUser = db.SystemUsers.Create();

                    sysUser.Email = user.email;
                    sysUser.Password = encrpPass;
                    sysUser.PasswordSalt = crypto.Salt;
                    sysUser.UserId = Guid.NewGuid();

                    db.SystemUsers.Add(sysUser);
                    db.SaveChanges();

                    return RedirectToAction("Index", "Home");

                }
            }
            else
            {
                ModelState.AddModelError("", "Login Data is incorrect");
            }
            return View(user);
        }
        private bool IsValid(string email, string password)
        {
            var Crypto = new SimpleCrypto.PBKDF2();
            bool IsValid = false;

            using(var db = new MainDbEntitiesContext())
            {
                var user = db.SystemUsers.FirstOrDefault(u => u.Email == email);

                if(user != null)
                {
                    if(user.Password == Crypto.Compute(password, user.PasswordSalt))
                    {
                        IsValid = true;
                    }
                }
            }

            return IsValid;
        }