There are some importatnt step to install Nginx with passenger on a newly installed Ubuntu server.
1. step: Install RVM in multi-user mode
2. step: install dependencie for MRI ruby. There are a list in the end of rvm install message. Install these packages.
3. step: rvm install 1.9.2
4. step: After ruby installed successfully you need to install passenger with
gem install passenger command.
5. step: You have got passenger gem, but haven't got nginx yet. Compile it from source: download, unpack, configure, make, make install.
6. step: nginx configuration