adding missing constructor argument

Interface/Wallet.java

@@ -13,7 +13,7 @@ public class Wallet extends AbstractWallet {
         final ActorSystem system = ActorSystem.create("FuCoin");
 
         // Create the 'greeter' actor
-        final ActorRef greeter = system.actorOf(Props.create(Wallet.class), "wallet");
+        final ActorRef greeter = system.actorOf(Props.create(Wallet.class, "Hans Wurst"), "wallet");
 
         // Create the "actor-in-a-box"
         final Inbox inbox = Inbox.create(system);