Create comparison and tester model.
Update landing page.
Add todo list to gitignore.
Use zurb foundation stylesheet.
Remove index in public folder and use slim instead of haml.
Setup assocations between tester, session, and comparison models.
Add original_id to Comparison to keep track of original order before randomization.
Create a set of randomized comparison for each session.
Rename root page from welcome#index to session#new.