update

src/main/java/PingPong/CollisionChecker.java

@@ -9,4 +9,8 @@ public class CollisionChecker {
     public Boolean didTouchPaddle(Rectangle ball, Rectangle paddle) {
         return ball.intersects(paddle);
     }
+
+    public Boolean didTouchLeftEdge(Integer ballXCoordinate) {
+        return ballXCoordinate <= 0;
+    }
 }