public static IServiceCollection AddExternalData(this IServiceCollection services, IConfiguration configuration)
        {
            var exchangeRatesServiceConfiguration = new OpenExchangeRatesServiceConfiguration();

            configuration.Bind("OpenExchangeRates", exchangeRatesServiceConfiguration);
            services.AddSingleton(exchangeRatesServiceConfiguration);
            services.AddScoped <ICurrencyExternalService, OpenExchangeRatesService>();
            return(services);
        }
 public OpenExchangeRatesService(OpenExchangeRatesServiceConfiguration configuration)
 {
     _host  = configuration.Host;
     _appId = configuration.ApiId;
 }