Salt the earth
Bare Rails 4 app
Use Rspec and Capybara for tests
Remove unused Rails internals (like AR)
Bare controller
Add code coverage to the suite
Switch to HAML
[WIP] Starting on outside-in tests
Get happy path working with non-dynamic Cron object
Separate CronParser and Cron classes
Convert fully from ERB to HAML
Extract cron form to partial and include everywhere
Remove useless (for now) spec
Still fake Cron object, but now all tests pass
Return new Cron instance
Remove unused pending specs
Start fleshing out the Cron class
Simplest Thing that Could Possibly Work™
I've committed some sins, but the tests pass

Can extract this out to objects later. I want to see how hairy it gets
once I put ranges and modulos in play.
Flesh out coverage, fix failing integration test