Passing environment variables to Ruby from Phusion Passenger. Update June 4 2013: This article is completely obsolete.
In Phusion Passenger 4, using SetEnv and PassEnv in Apache and env in Nginx works as expected. Detailed information can be found in the Phusion Passenger manual, section “About environment variables”. Ruby - haml collection and nil. Commit History for mbleigh's acts-as-taggable-on - GitHub.