npm install node-sass --save-dev

npm install sass-loader --save-dev 

rules: [
   {
    test: /\.vue$/,
    loader: 'vue-loader',
    options: vueLoaderConfig
   },
   {
    test: /\.js$/,
    loader: 'babel-loader',
    include: [resolve('src'), resolve('test')]
   },
   {
    test: /\.(png|jpe?g|gif|svg)(\?.*)?$/,
    loader: 'url-loader',
    query: {
     limit: 10000,
     name: utils.assetsPath('img/[name].[hash:7].[ext]')
    }
   },
   {
    test: /\.scss$/,
    loaders: ["style", "css", "sass"]
   },
   {
    test: /\.(woff2?|eot|ttf|otf)(\?.*)?$/,
    loader: 'url-loader',
    query: {
     limit: 10000,
     name: utils.assetsPath('fonts/[name].[hash:7].[ext]')
    }
   }
  ]
 }

<style lang="scss" scoped="" type="text/css"></style>