refactored Decorator pattern

Structural/Decorator/DoubleRoomBooking.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace DesignPatterns\Structural\Decorator;
+
+class DoubleRoomBooking implements Booking
+{
+    public function calculatePrice(): int
+    {
+        return 40;
+    }
+
+    public function getDescription(): string
+    {
+        return 'double room';
+    }
+}