Developers should be able to pass in their own Webpack configuration

[robmcguinness]

Similar too https://github.com/Availity/availity-workflow/blob/v1/webpack/index.js#L19.

function merge(config, webpackConfig) {

 webpackConfig.module.rules.push({
   test: /\.scss$/,
   loaders: ['style-loader', 'css-loader', 'sass-loader'],
   include: path.resolve(__dirname, '../'),
 });
}

module.exports = merge;