About three times a week, people message or email me with questions about their Rails app having permission problems. I’m posting this so people can figure this out themselves (not that I don’t appreciate the kind words that come with the questions).
$ mkdir /Library/WebServer/Rails
$ chgrp www /Library/WebServer/Rails
$ cd /Library/WebServer/Rails
$ rails ./MyWondrousRailsApp
So long as you create your Rails apps there, you shouldn’t have any problems. Basically, it looks like Rails needs read access to all of your application path – hence putting it in your home directory will result in your application throwing an error. Natch