Interestings

Beware of absolute paths when using unicorn and USR2

Using unicorns USR2 signal to restart does NOT re-read your unicorn config so be very careful with Capistrano deployments. See SO Q&A for details below:

http://stackoverflow.com/questions/9388074/restarting-unicorn-with-usr2-doesnt-seem-to-reload-production-rb-settings

Additionally you should specify several things in the config file, specifically the gemfile, or it won’t reload that either.
APP_ROOT = DIR
ENV['BUNDLE_GEMFILE'] = DIR/Gemfile