static void DeleteModel(int modelId)
        {
            using (var db = new BikeStoreContext())
            {
                var model = new Model { ModelId = modelId };

                db.Models.Attach(model);
                db.Models.Remove(model);
                db.SaveChanges();
            }
        }
        static int CreateModel()
        {
            int modelId = 0;

            using (var db = new BikeStoreContext())
            {
                var model = new Model { Name = "Domane 5.2", ListPrice = 3499.99m };

                db.Models.Add(model);
                db.SaveChanges();

                modelId = model.ModelId;
            }

            Console.WriteLine("New Model: " + modelId);

            return modelId;
        }