added proxy sample

proxy/src/main/java/com/iluwatar/WizardTowerProxy.java

@@ -0,0 +1,19 @@
+package com.iluwatar;
+
+public class WizardTowerProxy extends WizardTower {
+
+	private static final int NUM_WIZARDS_ALLOWED = 3;
+	
+	private int numWizards;
+	
+	@Override
+	public void enter(Wizard wizard) {
+		if (numWizards < NUM_WIZARDS_ALLOWED) {
+			super.enter(wizard);
+			numWizards++;
+		} else {
+			System.out.println(wizard + " is not allowed to enter!");
+		}
+	}
+	
+}