Add shoulda-matcher gem
Turn off deprecation warning for i18n
Add validations to DerbyEntry

- Change attribute total_votes to vote_count
Add Derbies table and foreign key on derby_entries to point to derbies
Implement Scrapers::DerbyPage

- Remove Scrapers::Document (spec interference)
- Add derby_id to Scrapers::DerbyEntry
Remove Scrapers::Votes since we are not implementing that
Create table for voters; Add join table between derby entries and voters
Add attributes to Voter and associations to Derby and DerbyEntry
Add haml gems
Create DerbiesController to display all or individual derbies
Create DerbyEntriesController + route