added variable for google tracking id

source/_layouts/default.haml

@@ -12,7 +12,7 @@ full_url:
 disqus_short_name: 
 
 google_custom_search_id:
-google_analytics: true
+google_analytics_tracking_id:
 
 ---
 
@@ -103,10 +103,10 @@ google_analytics: true
             }
             document.write('<script charset="utf-8" type="text/javascript" src="http://disqus.com/forums/#{page.disqus_short_name}/get_num_replies.js' + query + '"></' + 'script>');
           })();
-    - if page.respond_to? :google_analytics
+    - if page.respond_to? :google_analytics_tracking_id
       //Google Analytics code
       :javascript
         try {
-        var pageTracker = _gat._getTracker("UA-10876422-1");
+        var pageTracker = _gat._getTracker("#{google_analytics_tracking_id}");
         pageTracker._trackPageview();
         } catch(err) {}