Version of rails app

Hi all,
I want to ask about ideas of rails app versioning. I got app in
development and want to know version that client is running. I can
write some version string in application.html to show version...
Other idea is to find the newest file (its date) in rails app
directory - it can mark the "last change" of app - can someone give me
clues how to do this (find newest filedate in dir incrementally) in
Any other ideas of app versioning? I know that it would be good to
include revision number from repo like svn...

You could use an SVN keyword to insert the current revision in a file.

Put '$Revision$' in one of your files, then:
  $ svn propset svn:keywords Revision <your file>
to enable expansion of the keyword in your file.

Then, by looking in this file, you can determine which revision is in use.