install ruby 2.1 in ubuntu

ubuntu_ruby21.sh

#!/usr/bin/env bash

sudo apt-get -y update
sudo apt-get --no-install-recommends -y install build-essential openssl libreadline6 libreadline6-dev curl git-core zlib1g zlib1g-dev libssl-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt-dev autoconf libc6-dev libgdbm-dev ncurses-dev automake libtool bison pkg-config libffi-dev vim

git clone https://github.com/sstephenson/rbenv.git ~/.rbenv
git clone https://github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build

cd

echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
source ~/.bashrc && exec $SHELL -l

rbenv install 2.1.2
rbenv global 2.1.2

gem install chef --no-ri --no-rdoc