fix shapeApp class to Initialize the JavaFX application and create an instance of Drawer

src/main/java/shape/tp5/ShapeApp.java

@@ -2,25 +2,14 @@ package shape.tp5;
 import javafx.application.Application;
 import javafx.scene.Scene;
 import javafx.scene.layout.Pane;
+import javafx.scene.layout.StackPane;
 import javafx.stage.Stage;
 
 public class ShapeApp extends Application {
-
     @Override
     public void start(Stage primaryStage) {
         Drawer drawer = new Drawer(400, 400);
-
-        Circle circle1 = new Circle(100, 100, 50);
-        Circle circle2 = new Circle(300, 300, 60);
-        Rectangle rectangle = new Rectangle(150, 150, 100, 80);
-
-        drawer.add(circle1);
-        drawer.add(circle2);
-        drawer.add(rectangle);
-
-        Pane root = new Pane();
-        root.getChildren().add(drawer);
-
+        StackPane root = new StackPane(drawer);
         Scene scene = new Scene(root, 400, 400);
         primaryStage.setTitle("Éditeur de formes");
         primaryStage.setScene(scene);