Document how this works

[chriseppstein]

For mac:

• where are executables placed?
• How to uninstall? (even if manual -- I could ship a script to do the uninstall maybe?)
• Does it use system ruby or is ruby packaged with it. If packaged, where is that ruby placed?
• Does the user have rubygems when they are done? Can they upgrade using a gem command?

[wagenet]

IIRC, installation is to /usr/local you can uninstall by removing the directories.
Ruby is packaged with it and installed to the same location.
Ruby 1.9 is installed which includes Rubygems but they will not be able to upgrade the packaged gem with it since we lock things down using Bundler's standalone functionality.