rbenv

fancy_echo "Installing rbenv, to change Ruby versions ..."
  git clone git://github.com/sstephenson/rbenv.git ~/.rbenv

  if ! grep -qs "rbenv init" ~/.zshrc; then
    echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.zshrc

    echo 'eval "$(rbenv init - --no-rehash)"' >> ~/.zshrc
  fi

  source ~/.zshrc

fancy_echo "Installing rbenv-gem-rehash so the shell automatically picks up binaries after installing gems with binaries..."
  git clone https://github.com/sstephenson/rbenv-gem-rehash.git ~/.rbenv/plugins/rbenv-gem-rehash

fancy_echo "Installing ruby-build, to install Rubies ..."
  git clone git://github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build