Link to yurique's Scribble from the front page.

Instead of ScalaFiddle, which is unfortunately offline.

Author: sjrd

index.html

@@ -15,7 +15,7 @@ <h4>A safer way to build robust<br/> front-end web applications!</h4>
                 </div>
                 <div>
                     <a class="btn btn-theme" href="{{ site.baseurl }}/doc/tutorial/">Learn Scala.js</a>
-                    <a class="btn btn-theme" href="https://scalafiddle.io/">Try Scala.js in the browser</a>
+                    <a class="btn btn-theme" href="https://scribble.ninja/">Try Scala.js in the browser</a>
                 </div>
             </div>
         </div>