remove any existing service workers (#858)

docs/.vuepress/enhanceApp.js

@@ -2,4 +2,19 @@ import vSelect from '../../src/components/Select';
 
 export default ({Vue, options, router, siteData}) => {
   Vue.component('v-select', vSelect);
+
+  /**
+   * Remove service workers.
+   */
+  if (typeof navigator !== 'undefined' && 'serviceWorker' in navigator) {
+    navigator.serviceWorker.getRegistrations().then(registrations => {
+      registrations.forEach(registration => {
+        registration
+          .unregister()
+          .then(() => console.log('Service worker unregistered.'))
+          .catch(() => console.log('Error unregistering service worker.'));
+      });
+    });
+  }
+
 }