Added handling if the user is offline (#35)

src/ServiceWorker/sw.js

@@ -1,4 +1,21 @@
 /* eslint-disable no-console */
+/* eslint-disable no-undef */
 
-console.log('Hello from the service worker');
+// Cache assets
+workbox.routing.registerRoute(
+    // This regexp matches all files in precache-manifest
+    new RegExp('.+\\.(css|json|js|eot|svg|ttf|woff|woff2|png|html|txt)$'),
+    new workbox.strategies.StaleWhileRevalidate()
+);
 
+// Always send api reqeusts through the network
+workbox.routing.registerRoute(
+	new RegExp('(\\/)?api\\/v1\\/.*$'),
+	new workbox.strategies.NetworkOnly()
+);
+
+// Cache everything else
+workbox.routing.registerRoute(
+	new RegExp('.*'),
+    new workbox.strategies.StaleWhileRevalidate()
+);