ADD::added title to main program stage

now displays "Greenify - <username>"

src/Client/src/main/java/greenify/client/controller/UserController.java

@@ -71,6 +71,7 @@ public class UserController {
                 .getResource("stylesheets/dashboardStyle.css").toExternalForm());
         Stage appStage = new Stage();
         appStage.setScene(scene);
+        appStage.setTitle("Greenify - " + usernameField.getText());
         appStage.show();
     }