Update public/sw.js

public/sw.js

@@ -0,0 +1,22 @@
+
+// Service Worker for PWA
+const CACHE_NAME = 'vibrant-axolotl-glow-v1';
+const urlsToCache = [
+  '/',
+  '/styles/main.css',
+  '/script/main.js'
+];
+
+self.addEventListener('install', event => {
+  event.waitUntil(
+    caches.open(CACHE_NAME)
+      .then(cache => cache.addAll(urlsToCache))
+  );
+});
+
+self.addEventListener('fetch', event => {
+  event.respondWith(
+    caches.match(event.request)
+      .then(response => response || fetch(event.request))
+  );
+});