Do not use MacOS system Ruby · Mac Install Guide

Some developers use the system Ruby for running sysadmin scripts. That's fine, as long as you don't alter the system Ruby by attempting to update or add gems.For developing projects with Ruby, you should Install Ruby with Homebrew or use a version manager such as asdf, chruby, rbenv, or rvm. A version manager helps if you're juggling multiple projects and can't update all at once. For a guide that compares version managers and shows the best way to install Ruby, see Install Ruby on a Mac.