Recently had come accross the task of deploying a rails application with apache and passenger.
I did everything as prescribed in the way I used to but for some reasons I was shown the directory listing of the application instead of application being executed.
The change I had taken from my conventional way of giving the paths to using symbolic links.
Finally i figured out the solution as an issue with passenger and the way it treats symlinks:
here is what you need to put between the <directory> tags to get stuff working:
PassengerResolveSymlinksInDocumentRoot on
Hope it helps !