public static void Add(Customer auth)
        {
            var db = new MarinaEntities();

            db.Customers.Add(auth);
            db.SaveChanges();
        }
        public static void Update(Customer auth)
        {
            var db = new MarinaEntities();
            var authFromContext = db.Customers.SingleOrDefault(c => c.ID == auth.ID);

            authFromContext.FirstName = auth.FirstName;
            authFromContext.LastName  = auth.LastName;
            authFromContext.FirstName = auth.FirstName;
            authFromContext.LastName  = auth.LastName;
            authFromContext.City      = auth.City;
            authFromContext.Phone     = auth.Phone;
            db.SaveChanges();
        }