Add Ducksboard as an example app.

index.html

@@ -2638,6 +2638,26 @@ var model = localBackbone.Model.extend(...);
       </a>
     </div>
 
+    <h2 id="examples-ducksboard">Ducksboard</h2>
+
+    <p>
+    <a href="http://ducksboard.com/">Ducksboard</a> is an online dashboard
+      for your SaaS and business metrics, built with
+      <a href="http://twistedmatrix.com/">Twisted</a> and
+      <a href="http://www.djangoproject.com/">Django</a> and using WebSockets.
+      It can fetch data from popular SaaS providers or accept input through
+      a simple API.
+      Backbone is used throughout Ducksboard's interface, every widget,
+      dashboard and SaaS account is a Backbone model with several views
+      (data display, configuration view).
+    </p>
+
+    <div style="text-align: center;">
+      <a href="http://ducksboard.com/">
+        <img src="docs/images/ducksboard.png" alt="Ducksboard" class="example_image" />
+      </a>
+    </div>
+
     <h2 id="faq">F.A.Q.</h2>
 
     <p id="FAQ-events">