RBENV steps installation

Install RBENV

## Install rbenv
$ brew update && brew install rbenv ruby-build

## Install Ruby Version Choosed (2.6.5 it's the one I want)
$ rbenv install -v 2.6.5
$ rbenv global 2.6.5

## Check Ruby Version
$ ruby -v
ruby 2.6.5p114 (2019-10-01 revision 67812) [x86_64-darwin19]

$ ruby -e "puts (1..100).reduce(:+)"
5050

## Set ruby PATH to ZSH or Bash
$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile
$ source ~/.bash_profile

// if u use ZSH
$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.zshrc
$ source ~/.zshrc

## Check if everything is ok
$ rbenv init
$ curl -fsSL https://github.com/rbenv/rbenv-installer/raw/master/bin/rbenv-doctor | bash