Install Active Record

It's not great, but it's what everyone will expect.
Install MySQL adapter
Add simple database configuration file

This will get replaced in production, but it's useful to have one for
development work & running tests.
Create database connection in boot script
Convert Host, Mapping and Site to Active Record models
Remove unused RecordCollection class

Active Record does this for us now.
Use Active Record syntax for creating associated models

Active Record only gives you create_foo for one-to-one associations;
in these cases we have to use foos.create instead.

Testing the associations is annoying and unnecessary (Active Record
already has tests), so I'm removing the associated examples.
Update unit tests for Active Record models
Set up test database on Travis
Add transition app database structure

This is just the output of rake db:structure:dump from the transition app.
Load database structure on Travis
Connect to the transition tool database directly from bouncer

This strategy might not be acceptable in production, but it gets us off
the ground.
Add explicit Ruby version

The preview boxes run 1.9.2p290 by default, but we need at least 1.9.3
to use Active Support 4.