Install and initialize ActiveAdmin.
Add and configure ActiveAdmin with Devise.

+ Ref: http://dan.doezema.com/2012/02/how-to-implement-a-single-user-model-with-rails-activeadmin-and-devise/comment-page-1
+ Need to run rake db:migrate.
Remove debug alert from Marionette controller.
Add Capybara support for RSpec to spec_helper.
Add 'sign in' spec.
Add 'sign out' spec.
Add 'sign up' spec.
Add request helper.
Use request helper methods in specs.
Add 'edit user account' spec.
Refactor user model spec.
Refactor user controller specs.
Clean up user factory.
Add inherited_resources gem.
Use inherited_resources for controllers.
Add 'farm' feature.
Add 'view farms' scenario.
Add farm navigation link.
Add farm scaffold and specs.
add foreigner gem.