Add service worker to V1

docs/v1/manifest.appcache

@@ -1,2 +1,2 @@
 CACHE MANIFEST
-# itty bitty manifest 22.05.21
+# itty bitty manifest 22.05.21 

docs/v1/worker.js

@@ -0,0 +1,20 @@
+self.addEventListener('install', function(e) {
+ e.waitUntil(
+   caches.open('ittybitty-v1').then(function(cache) {
+     return cache.addAll([
+       '/',
+       '/favicon.ico'
+     ]);
+   })
+ );
+});
+
+self.addEventListener('fetch', function(event) {
+  event.respondWith(
+    caches.match(event.request).then(function(response) {
+      console.debug("Requested", event.request.url, response);
+
+      return response || fetch(event.request);
+    })
+  );
+ });