Added main structure

GifResizer/App.xaml.cs

@@ -1,6 +1,8 @@
 using System.Configuration;
 using System.Data;
 using System.Windows;
+using GifResizer.ViewModels;
+using GifResizer.Views;
 
 namespace GifResizer;
 
@@ -9,4 +11,13 @@ namespace GifResizer;
 /// </summary>
 public partial class App : Application
 {
+    protected override void OnStartup(StartupEventArgs e)
+    {
+        base.OnStartup(e);
+        
+        var viewModel = new MainViewModel();
+        var mainWindow = new MainWindow(viewModel);
+        
+        mainWindow.Show();
+    }
 }