Added Piwik support

app/views/layouts/_head.html.haml

@@ -12,6 +12,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
   = render 'layouts/google_analytics' if extra_config.has_key?('google_analytics_id')
+  = render 'layouts/piwik' if extra_config.has_key?('piwik_url') && extra_config.has_key?('piwik_site_id')
   -# Atom feed
   - if current_user

app/views/layouts/_piwik.html.haml

+:javascript
+  var _paq = _paq || [];
+  _paq.push(["trackPageView"]);
+  _paq.push(["enableLinkTracking"]);
+
+  (function() {
+    var u=(("https:" == document.location.protocol) ? "https" : "http") + "://#{extra_config.piwik_url}/";
+    _paq.push(["setTrackerUrl", u+"piwik.php"]);
+    _paq.push(["setSiteId", "#{extra_config.piwik_site_id}"]);
+    var d=document, g=d.createElement("script"), s=d.getElementsByTagName("script")[0]; g.type="text/javascript";
+    g.defer=true; g.async=true; g.src=u+"piwik.js"; s.parentNode.insertBefore(g,s);
+  })();

config/gitlab.yml.example

@@ -217,6 +217,10 @@ production: &base
     ## Google analytics. Uncomment if you want it
     # google_analytics_id: '_your_tracking_id'
+    ## Piwik analytics.
+    # piwik_url: '_your_piwik_url'
+    # piwik_site_id: '_your_piwik_site_id'
+
     ## Text under sign-in page (Markdown enabled)
     # sign_in_text: |
     #   ![Company Logo](http://www.companydomain.com/logo.png)