passenger with rvm

rvm_passenger.sh

# apt-get

# build-essential gcc libreadline6-dev libxslt-dev libxml2-dev zlib1g-dev libcurl4-openssl-dev libpcre3-dev

# http://www.blog.bridgeutopiaweb.com/post/install-rvm-passenger-nginx-and-rails-3-on-ubuntu-lucid-lynx/

rvm install 1.9.2

rvm 1.9.2 --passenger

rvm 1.9.2
gem install passenger

rvmsudo passenger-install-nginx-module

#use rvm by default
rvm 1.9.2-preview3 --default

#edit the nginx config file. mine is on /opt/nginx/conf/nginx.conf. just change username 

passenger_root /home/username/.rvm/gems/ruby-1.9.2-preview3/gems/passenger-2.2.15;
passenger_ruby /home/username/.rvm/bin/passenger_ruby;

#reboot if you can. I recommend rebooting over restarting/stopping and starting nginx server. reboot was actually the fix I needed after following all the steps above. 

sudo reboot 


#.rvmrc file on your Rails 3 app should contain. this may be optional but in case you've set a different ruby version, this helps. 

if [[ -s "~/.rvm/environments/ruby-1.9.2-preview3" ]] ; then
  . "~/.rvm/environments/ruby-1.9.2-preview3"
else
  rvm --create use  "ruby-1.9.2-preview3"