add constructeur

add method pointsCount()

src/main/java/shape/Decorator.java

 package shape;
 
-public class Decorator {
+public abstract class Decorator implements Shape {
+    protected Shape decoratedShape;
+
+    public Decorator(Shape decoratedShape ){
+        this.decoratedShape=decoratedShape;
+    }
+
+    public int pointsCount(){
+        return decoratedShape.pointsCount();
+    }
 }