First Rails Project

I set my web directory to in Control Panel -> Manage Accounts, and checked the Passenger checkbox. I then transferred all my files for my test Rails project from my own computer (where it does work) to the public subdirectory on DH.

But when I go to

all I get is an index listing. What have I done wrong?

The public directory in your rails project should match with the one on Dreamhost- that is, you want to upload your files onto the root directory of your domain.