feat: major refactor, cleanup and jest tests

examples/vuex-async/app.js

@@ -1,9 +1,9 @@
-import assign from 'object-assign'
 import Vue from 'vue'
 import store from './store'
 import router from './router'
 import App from './App.vue'
 
-const app = new Vue(assign(App, { router, store }))
+App.router = router
+App.store = store
 
-app.$mount('#app')
+new Vue(App).$mount('#app')