Adding book review ribbon.

build/share.html

@@ -7,4 +7,6 @@
 <script id="twitter-wjs" src="//platform.twitter.com/widgets.js"></script><script>!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs");</script>
 
   <p>&nbsp;<br></p>
-</div>
+</div>
+
+<a href="http://shop.oreilly.com/product/0636920025344/ReviewSubmit.do?sortby=publicationDate?pageId=0636920025344.IP"><img style="position: absolute; top: 0; right: 0; border: 0;" src="http://addyosmani.github.com/backbone-fundamentals/img/helpful.png" alt="Was this helpful? We'd love you to write a review."></a>