Update ruby version using rvm

update-rvm.sh

#!/bin/bash
#source::
#   http://stackoverflow.com/a/4574388/2636474

#First of all, update your RVM installation by running 
rvm get stable

#then to make sure you're running the new RVM version, you'll then need to run 
rvm reload #(or just open a new terminal).

#Once that's done, you can ask RVM to list the ruby versions available to install by running
rvm list known.

#In the output you should now see:
# MRI Rubies
#...
#[ruby-]1.9.2[-p320]
#...
#The square brackets around the patch level indicate that this is currently RVM's default patch level for ruby 1.9.2.
#Finally, to install the new ruby version, just run rvm install 1.9.2 - and wait for it to compile!