public ActionResult Criar(Midia model)
        {
            model.NumerodeCopiasDisponíveis = model.NumerodeCopias;
            repositorioMidia.Salvar(model);

            return RedirectToAction("Index");
        }
        public ActionResult Delete(Midia model)
        {
            repositorioMidia.Remover(model);

            return RedirectToAction("Index");
        }
        public ActionResult Editar(Midia model)
        {
            repositorioMidia.Salvar(model);

            return RedirectToAction("Index");
        }