add 'required' demo

Yvonne Yip · Yvonne Yip · commit b4bebc3b52ea · 2014-07-11T12:52:20.000-07:00
diff --git a/demo.html b/demo.html
@@ -39,6 +39,10 @@
 
     <br>
 
+    <paper-input label="Type something..." required error="This input requires a value!"></paper-input>
+
+    <br>
+
     <paper-input disabled label="I'm disabled"></paper-input>
 
     <br>
