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)));
}