title: Update PWA with firebase
body: <p>I made a progressive web application with firebase hosting. When I do some changes and I deploy I don't see the changes when I visit the app from browser.</p>
  
  <p>This is my code in sw.js:</p>
  
  <pre><code>self.addEventListener('install', function (event) {
    console.log('SW Installed');
    event.waitUntil(
      caches.open('static')
        .then(function (cache) {
          cache.addAll([
            '/',
            '/index.html',
            '/app.js',
            '/images/icons/icon-144x144.png'
          ]);
        })
    );
  });
  
  self.addEventListener('activate', function () {
    console.log('SW Activated');
  });
  
  self.addEventListener('fetch', function(event) {
    event.respondWith(
      caches.match(event.request)
        .then(function(res) {
          if (res) {
            return res;
          } else {
            return fetch(event.request);
          }
        })
    );
  });
  </code></pre>
  
  <p>This is my code in firebase.json:</p>
  
  <pre><code>{
    "hosting": {
      "public": "public"
    }
  }
  </code></pre>