Can't get Extract-text-webpack-plugin to work for webpack in production

Question

I am trying to compile sass/scss to css for production.

Essentially I was wondering how can you create a file structure for your assets in prod and get the scss files to get complied to css in prod? I have seen in many TUTs, everything gets dumped in a distor public folder. I can do it for JS, but how would you do it for all my assets? Example in the public folder there is a JS folder a image folder, css etc.

This is my webpack.config.js

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

module.exports = {
    entry: {
        app: ['./src/js/app.js']
    },
    output: {
        path: path.resolve(__dirname, 'public/js'),
        filename: 'app.bundle.js',
        publicPath: 'js'
    },
    devServer: {
        inline: true,
        contentBase: './public',
        port: 8888
    },
    module: {
        rules: [
            { 
              test: /\.scss$/, 
              use: ExtractTextPlugin.extract({
                fallback: 'style-loader',
                use : 'css-loader!sass-loader'
              })

            }
        ]
      },
    plugins: [
            new ExtractTextPlugin('styles.css')
    ]
}