This command doesn't work as I had rails 6 installed on my PC
# README
rails new app_name -m https://www.refinerycms.com/t/4.0.0
Instead we should install rails version 5.1.x and generate new app with the Rails 5 version
gem install rails -v 5.1.7
rails _5.1.7_ new app_name -m https://www.refinerycms.com/t/4.0.0