webpack.config.js

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

module.exports = {

  entry: './client/index.js',

  output: {
    path: __dirname + '/public',
    filename: 'bundle.js'
  },

  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        include: path.join(__dirname, 'client'),
        use: ['react-hot-loader', 'babel-loader?' + JSON.stringify({
          cacheDirectory: true,
          presets: ['es2015', 'react', 'stage-1']
        })],
      },
      {
        test: /\.(png|jpg|gif|svg|eot|ttf|woff|woff2)$/,
        use: {
          loader: 'url-loader',
          options: {
            limit: 100000,
          },
        },
      },
      {
        test: /\.css$/,
        include: /node_modules/,
        use: ExtractTextPlugin.extract({
          fallback: 'style-loader',
          use: [
            {
              loader: 'css-loader',
              query: {
                importantLoaders: 1,
              }
            },
            {
              loader: 'postcss-loader',
            },
          ],
        })
      }
    ]
  },
  plugins: [
    new ExtractTextPlugin('styles.css'),
  ]

};