Hugo-module "Setup a site from scratch" instructions are missing steps

[chalin]

Both the TL;DR and the "Detailed steps" need to mention Install PostCSS.

[a-h]

And to create postcss.config.js as per step 3 of https://gohugo.io/hugo-pipes/postcss/

module.exports = {
  plugins: [
    require('autoprefixer')
  ]
};

If you don't want error:

Error: error building site: POSTCSS: failed to transform "/scss/main.css" (text/css): Error: Loading PostCSS Plugin failed: Cannot find module 'autoprefixer'