Goal: write a simple Mad Lib web application.

To do this, we'll need to understand how to write Ruby classes and methods,
use advanced string formatting, and work with file handles and persistence.

Prerequisites:

* install Ruby 1.9 on your computer
* know how to launch and use the command-line terminal
* know how to use a programmer's text editor like Vim, Emacs, or TextWrangler
* be able to use Git to check out projects from GitHub

How to get install Ruby:

Mac OS X comes with Ruby pre-installed, but because we're going to be using a
bunch of non-standard libraries, we'll install our own version.

The most flexible (though not necessarily easiest) way to do this is via two
open source tools, rbenv and ruby-install. Both are available from GitHub:

https://github.com/sstephenson/rbenv
https://github.com/sstephenson/ruby-build

Follow the instructions in the "Installation" section of each project. Don't
worry if this is confusing; we'll leave time for the install during the class
on Monday.