Fix icons broken by #15.

Basically just had to run `rails generate bootstrap:install less`.
See: https://github.com/seyhunak/twitter-bootstrap-rails#installing-the-less-stylesheets
Change/add a few fontawesome icons.
Merge pull request #17 from gregleaver/icon-fix

Icon fix
Setup grunt for js/coffee linting
Add rails_best_practices gem.

Include test files in analysis.
Add `grunt lint` and `rake rails_best_practices` to travis script.
Add index to documents table.
Remove empty helpers.

http://rails-bestpractices.com/posts/72-remove-empty-helpers
Protect against mass assignment.

http://rails-bestpractices.com/posts/148-protect-mass-assignment
Remove trailing whitespace.
Simplify render in controllers.

http://rails-bestpractices.com/posts/62-simplify-render-in-controllers
Replace instance variable with locals in partials.

http://rails-bestpractices.com/posts/27-replace-instance-variable-with-local-variable
Tell travisci to install grunt-cli
Merge pull request #18 from gregleaver/code_quality

Add jshint, coffeelint, rails_best_practices