add tracking code to main.js

public/js/main.js

@@ -14,4 +14,14 @@
         js.setAttribute("src", "https://d2xxklvztqk0jd.cloudfront.net/js/highlight.js");
         var t = document.getElementsByTagName('script')[0]; t.parentNode.insertBefore(js, t);
     }
-})(window);
+
+	// analytics code
+	(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-9214337-4', 'auto');
+	ga('send', 'pageview');
+
+
+})(window);