Add MemberListWindow

Elwig/Windows/MainWindow.xaml.cs

@@ -33,6 +33,11 @@ namespace Elwig.Windows {
             w.Show();
         }
 
+        private void Button3_Click(object sender, RoutedEventArgs evt) {
+            var w = new MemberListWindow();
+            w.Show();
+        }
+
         private void Button4_Click(object sender, RoutedEventArgs evt) {
             Utils.RunBackground("PDF Generation", async () => {
                 using var letter = new BusinessLetter("Test Dokument", Context.Members.First());