old_contents: const env = process.env.NODE_ENV
  
  const config = {
    port: '{{port}}',
    title: '{{name}}',
    vendor: [
      'react',
      'react-dom',
      'redux',
      'react-redux',
      'react-router',
      'redux-thunk'
    ],
    postcss: [
      require('postcss-cssnext')({
        browsers: ['last 2 versions', 'ie > 8']
      })
    ]
  }
  
  if (env === 'production') {
    config.babel.presets.push('react-optimize')
  } else {
    config.babel.presets.push('react-hmre')
  }
  
  module.exports = config
  
new_contents: const config = {
    port: '{{port}}',
    title: '{{name}}',
    vendor: [
      'react',
      'react-dom',
      'redux',
      'react-redux',
      'react-router',
      'redux-thunk'
    ],
    postcss: [
      require('postcss-cssnext')({
        browsers: ['last 2 versions', 'ie > 8']
      })
    ]
  }
  
  module.exports = config
  
subject: Update config.js