public void Start(ClientConsole console)
        {
            console.PrintCustomersList(CustomerSingleton.Instance.Customers);
            int  userMenuChoice = console.ChooseMenu();
            bool validUser      = false;

            if (userMenuChoice > CustomerSingleton.Instance.Customers.Count)
            {
                curCust = new Customer(console.GetString("Enter name: "));
                CustomerSingleton.Instance.Customers.Add(curCust);
                validUser = true;
            }
            else
            {
                curCust = CustomerSingleton.Instance.Customers[userMenuChoice - 1];
                if (curCust.PasswordCheck(console.GetString("Enter password: "******"Invalid password.");
            }
        }