IHost host = Host.CreateDefaultBuilder(args)
    .ConfigureAppConfiguration((hostingContext, configuration) =>
    {
        configuration.Sources.Clear();
        IHostEnvironment env = hostingContext.HostingEnvironment;
        configuration
            .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);
            //.AddJsonFile($"appsettings.{env.EnvironmentName}.json", true, true);
        IConfigurationRoot configurationRoot = configuration.Build();
    })
    .ConfigureServices((hostContext, services) =>
    {
        services.Configure<SiteSettings>(options => hostContext.Configuration.Bind(options));

  [SanitizeInput] public IActionResult Add (string address)