Add google analytics tracking code to docs page.

Author: DGivney

docs/index.html

@@ -1825,6 +1825,17 @@ <h5>Writing our program</h5>
     <script src="./assets/bootstrap/js/bootstrap.min.js"></script>
     <script src="./assets/script.js"></script>
 
+    <script>
+      (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
+      (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
+      m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
+      })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
+
+      ga('create', 'UA-41213327-1', 'asmtutor.com');
+      ga('send', 'pageview');
+
+    </script>
+
   </body>
 </html>