protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
IUnityContainer container = DependencyConfiguration.BuildUnityContainer();
IDarkSkyService darkSkyService = container.Resolve <DarkSkyService>();
ICityService cityService = container.Resolve <CityService>();
MainWindow mainWindow = new MainWindow(new MainWindowViewModel(darkSkyService, cityService));
mainWindow.Show();
}