private ShopInformation()
 {
     Customers = new List<Customer>();
     Customers.Add(new Customer("test", "test"));
     Administrators = new List<Admin>();
     Administrators.Add(new Admin("Root", "qwerty"));
     AvailableProducts = new ProductsList();
     SoldProducts = new ProductsList();
     CurrentPromotion = new Promotion();
 }
 public Cart(string comment = null)
 {
     this.CartList = new ProductsList();
     this.Comment = comment;
 }