Install ruby in Centos 7 with rbenv

ruby-install

# Adapted from this gist
# https://gist.github.com/soardex/e95cdc230d1ac5b824b3
# I changed .bash_profile to .bashrc since docker opens bash as non-login shell
# Also, I added 'gem update --system' because bundler was complaining about it

RUBY_VERSION=2.3.0

# install build dependencies
sudo yum install -y git-core zlib zlib-devel gcc-c++ patch readline readline-devel \
  libyaml-devel libffi-devel openssl-devel make bzip2 \
  autoconf automake libtool bison curl sqlite-devel

# clone and install rbenv environment
cd ~
git clone git://github.com/sstephenson/rbenv.git .rbenv
git clone git://github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build
echo 'export PATH="$HOME/.rbenv/bin:$HOME/.rbenv/plugins/ruby-build/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc

# re-init bash
source ~/.bashrc

# install latest ruby
rbenv install -v $RUBY_VERSION

# sets the default ruby version that the shell will use
rbenv global $RUBY_VERSION

# to disable generating of documents as that would take so much time
echo "gem: --no-document" > ~/.gemrc

# bundler complained that this should be run.
gem update --system

# install bundler
gem install bundler

# must be executed everytime a gem has been installed in order for the ruby executable to run
rbenv rehash