System wide RVM

rmvm-system-wide.sh

sudo su
bash <<(curl -s https://rvm.beginrescueend.com/install/rvm)
apt-get install zlib1g-dev libssl-dev libreadline5-dev
rvm install 1.9.2
rvm 1.9.2

add rvm script below to your .bashrc and to /root/.bashrc
# Load RVM if it is installed,
#  first try to load  user install
#  then try to load root install, if user install is not there.
if [ -s "$HOME/.rvm/scripts/rvm" ] ; then
  . "$HOME/.rvm/scripts/rvm"
elif [ -s "/usr/local/rvm/scripts/rvm" ] ; then
  . "/usr/local/rvm/scripts/rvm"
fi

set defaults via rvm use xxx –default
Re-login (or you get permisson denied on gem install).
rvmsudo xxx to use gems as sudo.