adding service worker

src/js/app.js

@@ -220,7 +220,13 @@
 	};
 
 	async function run() {
+		
+		app.registration = await navigator.serviceWorker.register('/sw.js', {scope: '/'})
+		.then(async function(sw) {
+			console.info('ServiceWorker registered: ', sw.scope);
 
+			return sw;
+		});
 	};
 
 	app.nextTick = function() {

src/js/sw.js

-
+importScripts('https://storage.googleapis.com/workbox-cdn/releases/5.1.3/workbox-sw.js');
\ No newline at end of file
+
+if (workbox) {
+  console.log(`Yay! Workbox is loaded 🎉`);
+
+  workbox.precaching.precacheAndRoute(self.__WB_MANIFEST);
+
+	workbox.googleAnalytics.initialize();
+
+} else {
+  console.log(`Boo! Workbox didn't load 😬`);
+}