Please follow step-by-step success is your's : LOL
Copy production.rb to staging.rb in config/environments
cp production.rb staging.rb
Add a staging entry to your config/database.yml
Your database.yml is should like this :
Add log file for staging env.
chmod 0666 log/staging.log
For just check. if the env is working for staging.
ruby script/server -e staging
For The Phusion Passenger (mod_rails) You have to put "RailsEnv staging" in your Apache Virtual Host.
< virtualhost XX.XX.XX.XX:80 >
< /VirtualHost >
and check website.