public IActionResult AddNewRenter(Renters renter)
        {
            renter.RenterId = Guid.NewGuid().ToString();
            Cars c = carsLogic.GetOneCar(renter.CarId);

            c.Available = false;
            carsLogic.Save();
            rentersLogic.InsertRenter(renter);

            return(RedirectToAction(nameof(ListCars)));
        }