webpack.production.config.js

{
  ...
  output: {
    path: outputPath,
    publicPath: "https://cnd.com/production/js/", // hostname needs to match Rails config
    filename: '[name]-[chunkhash].js'
  },
  plugins: [
    new AssetsPlugin({ path: outputPath }),
    new webpack.optimize.UglifyJsPlugin(),
    new webpack.optimize.OccurenceOrderPlugin(true)
  ]
  ...
}