Install Ruby

Windows Instructions

1. To install Ruby following this link.
2. Select version 2.6.5 or latest with devkit.
3. When prompt for installing MSYS use option 1.

Linux / MacOS

1. Install Homebrew (Linux / MacOS)

2. Install Ruby using these commands:

   brew install rbenv ruby-build
   
   # Add rbenv to bash so that it loads every time you open a terminal
   echo 'if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi' >> ~/.bash_profile
   source ~/.bash_profile
   
   # Install Ruby
   rbenv install 2.6.5
   rbenv global 2.6.5
   ruby -v
   
   

More info: Follow this link