Fix 'hello' example.

Author: ovvn

hello/index.js

@@ -4,7 +4,12 @@ app.loadViews(__dirname);
 // Routes render on client as well as server
 app.get('/', function(page, model) {
   // Subscribe specifies the data to sync
-  model.subscribe('hello.message', function() {
+  var message = model.at('hello.message');
+  message.subscribe(function(err) {
+    if (err) return next(err);
+    if (message.get() == null) {
+      message.create('');
+    }
     page.render();
   });
 });