rails4のサブディレクトリ運用

http://quickhack.net/nom/blog/2012-09-19-rails-with-relative-url-root.html#sec-6

config.ruは

map ActionController::Base.config.relative_url_root || "/" do
  run Rails.application
end

起動は

RAILS_RELATIVE_URL_ROOT='/yourdict' unicorn -p 8080 -E production -D

apacheとかは

ProxyPass /yourdict http://localhost:8080/yourdict
ProxyPassReverse /yourdict http://localhost:8080/yourdict

で。