Как добавить минимизацию css в webpack?

{
  loader: 'css-loader',
  options: {
    minimize: true
  }
}

'use strict'

const HtmlWebpackPlugin = require('html-webpack-plugin');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const webpack = require('webpack');
const path = require('path');

module.exports = {
  entry: {
    bundle: './src/app.js',
    style: './styles/main.sass'
  },
  output: {
    filename: '[name].min.js',
    path: path.resolve(__dirname, 'client/public')
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['es2015', 'react']
          }
        }
      },
      {
        test: /\.pug$/,
        use:  [
          'html-loader',
          {
          loader: 'pug-html-loader',
          options: {
            data: {}
          }}
        ]
      },
      {
        loader: 'css-loader',
        options: {
          minimize: true
        }
      },
      {
        test: /\.sass$/,
        use: ExtractTextPlugin.extract({
          fallback: 'style-loader',
          use: ['css-loader', 'sass-loader'],
          publicPath: path.resolve(__dirname, 'styles/')
        })
      }
    ]
  },
  resolve: {
    modules: ['node_modules'],
    extensions: ['.js', '.json', '.jsx', '.css', '.pug', '.sass']
  },
  //watch: true,
  plugins: [
    new webpack.optimize.UglifyJsPlugin({
      compress: {
        warnings: true
      }
    }),
    new HtmlWebpackPlugin({
      template: path.resolve(__dirname, 'views/index.pug'),
      inject: 'body'
    }),
    new ExtractTextPlugin({
      filename: '[name].min.css',
      disable: false,
      allChunks: true
    })
  ]
};