How to run rails app exe on port other than 3000?

We have managed to package our rails application into an exe using the
steps given at:
http://www.erikveen.dds.nl/distributingrubyapplications/rails.html

When we start the exe, it starts on port 3000. But when we will be
installing it at the clients’ site, this may not work as some other
rails application may be running on that port.
What can we do to configure the port on which the application is
supposed to run?

Thanks,
Yash

Simple hack is to edit railties/lib/commands/servers/webrick.rb and
change
the default.

A better way is to use ARGV, you can probably do it by passing an
appropriate command line parameter somewhere. Just play around with it
till
it works.

-Jonathan