howto: real author vs. repos author

[Uwe Mayer]

Hi,

I maintain a project under GPL. People started using it, sending me patches
and extensions to the program. I maintain a local versioning system to keep
track of revisions. 
I need to know the propper way how to credit the users for patches or
extensions send to me and having a $Author$ keyword substitution from my
versioning system in the header of my files. 

I.e. if I recieve a script which was copied using a template from me, how do
I correctly mention the other user in the header? Can I still have a
$Author$ keyword? Is it ok to add the file to my local repository?
Would the following suffice:

# Authors: foo, bar
# $Author: bar $
# $Rev: 93 $

Where "bar" would be the original author, as well as the maintainer of the
repository and "foo" the user having extended the file.

Thanks
Uwe