Add Google Analytics code

Author: lcharette

app/config/production.php

@@ -27,4 +27,12 @@
             ],
         ],
     ],
+    'site' => [
+        'analytics' => [
+            'google' => [
+                'code'    => 'G-JLM4TB5D6Y',
+                'enabled' => true,
+            ],
+        ],
+    ],
 ];

app/templates/pages/partials/analytics.html.twig

@@ -0,0 +1,14 @@
+{% if site.analytics.google.code and site.analytics.google.enabled %}
+    <script async src="https://www.googletagmanager.com/gtag/js?id={{ site.analytics.google.code }}"></script>
+    <script>
+    window.dataLayer = window.dataLayer || [];
+    function gtag(){dataLayer.push(arguments);}
+    gtag('js', new Date());
+
+    gtag('config', '{{ site.analytics.google.code }}');
+    </script>
+{% elseif site.debug.info %}
+    <script>
+        console.log("Google Analytics is disabled or code has not been set.");
+    </script>
+{% endif %}