Add privacy page, include Matomo in production

app/assets/javascripts/matomo.js

@@ -0,0 +1,26 @@
+var idSite = 1;
+var matomoTrackingApiUrl = 'https://matomo.pfischbeck.de/matomo.php';
+
+var _paq = window._paq || [];
+_paq.push(['setTrackerUrl', matomoTrackingApiUrl]);
+_paq.push(['setSiteId', idSite]);
+_paq.push(['trackPageView']);
+_paq.push(['enableLinkTracking']);
+
+// Send Matomo a new event when navigating to a new page using Turbolinks
+// (see https://developer.matomo.org/guides/spa-tracking)
+(function() {
+    var previousPageUrl = null;
+    addEventListener('turbolinks:load', function(event) {
+        if (previousPageUrl) {
+            _paq.push(['setReferrerUrl', previousPageUrl]);
+            _paq.push(['setCustomUrl', window.location.href]);
+            _paq.push(['setDocumentTitle', document.title]);
+            if (event.data && event.data.timing) {
+                _paq.push(['setGenerationTimeMs', event.data.timing.visitEnd - event.data.timing.visitStart]);
+            }
+            _paq.push(['trackPageView']);
+        }
+        previousPageUrl = window.location.href;
+    });
+})();