Merge branch 'release/1.2.0' into feature/refactor_taggings

Up: Gemfile.next with Puma

Add: Puma instead of Unicorn (with default config.)

Add: 12-Factor gem, which includes STDOUT logging (for Heroku)

Fix: Devise & email tweaks

Up: Rails v3.2.19, other gems updated

Up: e-mail address from which Devise sends messages

Add: Airbrake config file

Up: year in README

Merge branch 'hotfix/1.1.3/email-subject' into release/1.1.4