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:
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