add vue extension on resolve (#146)

This is issue fix for 
#130

Author: feats-choi

template/webpack.config.js

@@ -43,7 +43,8 @@ module.exports = {
   resolve: {
     alias: {
       'vue$': 'vue/dist/vue.esm.js'
-    }
+    },
+    extensions: ['*', '.js', '.vue', '.json']
   },
   devServer: {
     historyApiFallback: true,