public ActionResult Index()
        {
            var viewModel = new CurrencyViewModel()
            {
                Currencies = CurrencyService.GetCurrencies()
            };

            return View(viewModel);
        }
 public ActionResult Index(CurrencyViewModel viewModel)
 {
     var context = GlobalHost.ConnectionManager.GetHubContext<CurrencyHub>();
     viewModel.Currencies.ForEach(c => context.Clients.All.updateCurrency(c.Code, c.Price));
     return View(viewModel);
 }