Installation instructions for Ubuntu
Installation instructions for Ubuntu

Add instructions for how to install rcm on Ubuntu using the
[~martin-frost/thoughtbot-rcm
PPA](https://launchpad.net/~martin-frost/+archive/ubuntu/thoughtbot-rcm)

zachlatta/rcm,devm33/rcm,devm33/rcm,fgandellini/rcm,thoughtbot/rcm,devm33/rcm,Frost/rcm,tejasmanohar/rcm,ali/rcm,thoughtbot/rcm,tejasmanohar/rcm,ali/rcm,Frost/rcm,TheLinuxKitten/rcm,tejasmanohar/rcm,ali/rcm,Frost/rcm,fgandellini/rcm,TheLinuxKitten/rcm,fgandellini/rcm,thoughtbot/rcm,zachlatta/rcm,TheLinuxKitten/rcm,Frost/rcm,tejasmanohar/rcm,devm33/rcm,zachlatta/rcm,ali/rcm,fgandellini/rcm,zachlatta/rcm,TheLinuxKitten/rcm