public IActionResult Index()
        {
            var viewmodel = new CustomerAccountsViewModel
            {
                Accounts  = BankRepository.Accounts,
                Customers = BankRepository.Customers
            };

            return(View(viewmodel));
        }
        public IActionResult Index()
        {
            var model = new CustomerAccountsViewModel();

            model.Customers = _repository.Customers;

            foreach (var customer in model.Customers)
            {
                customer.Accounts = _repository.Accounts.Where(a => a.AccountHolder == customer.Id).ToList();
            }

            return(View(model));
        }