rbenv install & config

rbenv

$ brew install rbenv
$ rbenv init

$ echo 'eval "$(rbenv init -)"' >> ~/.zshrc
$ curl -fsSL https://github.com/rbenv/rbenv-installer/raw/master/bin/rbenv-doctor | bash
$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.zshrc
$ rbenv uninstall 2.3.1

rbenv plugin ruby-build

$ mkdir -p "$(rbenv root)"/plugins
$ git clone https://github.com/rbenv/ruby-build.git "$(rbenv root)"/plugins/ruby-build

rebenv plugin gemset

$ git clone git://github.com/jf/rbenv-gemset.git $HOME/.rbenv/plugins/rbenv-gemsetshell

Reference:

rbenv rbenv-ruby-build rbenv-gemset