Preparation: Setup of Cucumber and RSpec
Part 1: Add a Director field to Movies
add director.feature
finish first scenario

add director info to an existing movie,
and doesn't require creating any new views or controller actions
(but does require modifying existing views,
and will require creating a new step definition
and possibly adding a line or two to features/support/paths.rb).
finish second and third scenario

The second lets you click a new link on a movie details page
"Find Movies With Same Director", and shows all movies that share
the same director as the displayed movie.

The third handles the sad path, when the current movie
has no director info but we try to do "Find with same director" anyway.