webpack.config.js

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

module.exports = {
  entry: './app/javascripts/app.jsx',
  output: {
    path: path.resolve(__dirname, 'build'),
    filename: 'bundle.js'
  },
  plugins: [
    // Copy our app's index.html to the build folder.
    new CopyWebpackPlugin([
      { from: 'public'},
    ]),
    new ExtractTextPlugin('bundle.css')
  ],
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
/*          {
            loader: 'style-loader'
          }, */
          {
            loader: 'css-loader',
            options: {
              modules: true
            }
          }
        ]
      },
      {
        test: /\.scss$/,
        use: ExtractTextPlugin.extract({
//          fallback: 'style-loader',
          use: [
            {
              loader: 'css-loader',
              options: {
                sourceMap: true
              }
            },
            {
              loader: 'sass-loader',
              options: {
                sourceMap: true
              }
            }
          ]
        })
      },
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: [
          {
            loader: 'babel-loader',
            options: {
              presets: [
                ['es2015', {'modules': false}],
                'react'
              ]
            }
          }
        ]
      }
    ]
  }
}