Installing Ruby - "Installing requirements for ubuntu"

[cdenneen]

Unless user you are installing as has sudo NOPASSWD privileges this install fails to run "apt-get --quiet --yes update".
If the dependencies are installed already it would work.

There needs to be a exec run prior to the install of ruby to install the rvm requirements.

I'm going to fork and make a pull request.

[ivanxuu]

Thanks for the patches!