How to install

Requirements

Gem should work on any OS that support Ruby language - Linux, Mac, Windows. You just need ruby and git.

Install Ruby and Git (Windows)

The best way to install Ruby on windows is using rubyinstaller.
Install Git by following GitHub guide to install Git on Windows.

Install Ruby and Git (Linux)

I strongly recommend installing Ruby with some version manager like rbenv or rvm.
Here you can find rbenv for details, but installation command is:

sudo apt install rbenv

sudo apt install git