docs: update demo

Author: ktquez

demo/src/components/HelloWorld.vue

@@ -55,15 +55,9 @@
 </template>
 
 <script>
-import { FocusLoop } from '../../vue-focus-loop'
-
 export default {
   name: 'HelloWorld',
 
-  components: {
-    FocusLoop
-  },
-
   props: {
     msg: String
   },

demo/src/main.js

@@ -1,8 +1,10 @@
 import Vue from 'vue'
 import App from './App.vue'
+import VueFocusLoop from '../../src'
 
 Vue.config.productionTip = false
+Vue.use(VueFocusLoop)
 
 new Vue({
-  render: h => h(App),
+  render: h => h(App)
 }).$mount('#app')