old_contents: var webpack = require('webpack');
  var common = require('./webpack.common.config.js');
  var assign = require('object-assign');
  
  module.exports = assign(common, {
      debug: true,
      plugins: common.plugins.concat([
          new webpack.optimize.DedupePlugin(),
          new webpack.optimize.OccurenceOrderPlugin(),
          new webpack.optimize.AggressiveMergingPlugin(),
          new webpack.optimize.UglifyJsPlugin({exclude: /conference.*?\.js$/})
      ])
  });
  
new_contents: var webpack = require('webpack');
  var common = require('./webpack.common.config.js');
  var assign = require('object-assign');
  
  module.exports = assign(common, {
      plugins: common.plugins.concat([
          new webpack.optimize.DedupePlugin(),
          new webpack.optimize.OccurenceOrderPlugin(),
          new webpack.optimize.AggressiveMergingPlugin(),
          new webpack.DefinePlugin({
              'process.env': {
                  NODE_ENV: JSON.stringify('production')
              }
          }),
          new webpack.optimize.UglifyJsPlugin({exclude: /conference.*?\.js$/})
      ])
  });
  
subject: Set NODE_ENV to production