This will set you up with basic automated testing for code retreat
practice using Conway's Game of Life. It will create a "code_retreat"
gemset, install the needed gems, and set the gemset as your default
whenever you enter the working directory.

Set it up by rvm use-ing your chosen ruby version, then running this
on the command line:

    ruby setup.rb

When you want to start over, reset like this:

    ruby reset.rb

This will remove all your code changes.

If you have the screencapture application installed, this will
take a screenshot every time you save your file, so you can look
back fondly on your work :)  These will be saved in the "screencaptures"
directory as png files you can later turn into a slideshow if you want.

screenshots are timestamped, and not erased when you reset.