I would like to very strongly discourage the inclusion of a passenger module. No offense to passenger, but in terms of Nginx it tends to cause a massive number of headaches. In general, the Nginx community not only won't support the use of passenger, but also will offer no support when it's involved. I would recommend not adding support for passenger. If doing so then a separate package is definitely the way to go, but it's very likely that it will become a support headache.
18:15 < ngxbot> Passenger is neither supported nor endorsed by the community, please don't ask about it. Ideally, please don't use it. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org