Update _header.html.erb

Author: justin808

app/views/pages/_header.html.erb

@@ -30,5 +30,10 @@
     <%= link_to "The React on Rails Doctrine",
                 "http://www.shakacode.com/2016/01/27/the-react-on-rails-doctrine.html" %>.
   </li>
+  <li>
+    See our React Native Client: 
+    <%= link_to "shakacode/react-native-tutorial",
+                "https://github.com/shakacode/react-native-tutorial" %>.
+  </li>
 </ul>
 <hr/>