feature[permission]: add v-permission (#653)

src/directive/permission/index.js

@@ -0,0 +1,13 @@
+import permission from './permission'
+
+const install = function(Vue) {
+  Vue.directive('permission', permission)
+}
+
+if (window.Vue) {
+  window['permission'] = permission
+  Vue.use(install); // eslint-disable-line
+}
+
+permission.install = install
+export default permission