public ActionResult GetAllRestaurantsFromCity(int id)
        {
            var  cityidlist  = RestaurantManager.GetCitiesId();
            bool validCityId = false;


            //if the city code is not in the database or not correct, it display a the index error view
            foreach (int index in cityidlist)
            {
                if (id == index)
                {
                    validCityId = true;
                }
            }

            if (validCityId == true)
            {
                var restaurantlist = RestaurantManager.GetRestaurantsFromCity(id);

                return(View(restaurantlist));
            }
            else
            {
                return(RedirectToAction(nameof(IndexError)));
            }
        }