refactor: IE polyfills

Author: xidedix

src/main.js

@@ -1,10 +1,17 @@
 // The Vue build version to load with the `import` command
 // (runtime-only or standalone) has been set in webpack.base.conf with an alias.
+import 'core-js/es6/promise'
+import 'core-js/es6/string'
+import 'core-js/es7/array'
+// import cssVars from 'css-vars-ponyfill'
 import Vue from 'vue'
 import BootstrapVue from 'bootstrap-vue'
 import App from './App'
 import router from './router'
 
+// todo
+// cssVars()
+
 Vue.use(BootstrapVue)
 
 /* eslint-disable no-new */