I would highly suggest using a package manager and a Ruby Environment Manager.
On Mac:
brew update
brew install ruby
# If you use bash
echo 'export PATH=/usr/local/Cellar/ruby/2.4.1_1/bin:$PATH' >> ~/.bash_profile
# If you use ZSH:
echo 'export PATH=/usr/local/Cellar/ruby/2.4.1_1/bin:$PATH' >> ~/.zprofile
You can do that but I suggest using an Environment Manager for Ruby.
You have rbenv and RVM.
IMO go for rbenv:
brew install rbenv ruby-build
# bash
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile
echo 'eval "$(rbenv init -)"' >> ~/.bash_profile
# zsh
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.zprofile
echo 'eval "$(rbenv init -)"' >> ~/.zprofile
# list all available versions:
rbenv install -l
# install a Ruby version:
rbenv install 2.4.1
# set ruby version for a specific dir
rbenv local 2.4.1
# set ruby version globally
rbenv global 2.4.1
rbenv rehash
gem update --system