To improve tracking of who did what, we use the "sign-off" procedure
introduced by the Linux kernel.  The sign-off is a simple line at the
end of the explanation for the patch, which certifies that you wrote
it or otherwise have the right to pass it on as an open-source patch.
The rules are pretty simple: if you can certify the Developer's
Certificate of Origin 1.1 (see the developer-certificate-of-origin
file), then you just add a line saying

  Signed-off-by: Random J Developer <random@developer.example.org>

using your real name (sorry, no pseudonyms or anonymous
contributions).  This line can be automatically added by git if you
run the git-commit command with the -s option.

If you like, you can put extra tags at the end:

1. "Reported-by:" is used to credit someone who found the bug that
   the patch attempts to fix.
2. "Acked-by:" says that the person who is more familiar with the area
   the patch attempts to modify liked the patch.
3. "Reviewed-by:", unlike the other tags, can only be offered by the
   reviewer and means that she is completely satisfied that the patch
   is ready for application.  It is usually offered only after a
   detailed review.
4. "Tested-by:" is used to indicate that the person applied the patch
   and found it to have the desired effect.

You can also create your own tag or use one that's in common usage
such as "Thanks-to:", "Based-on-patch-by:", or "Mentored-by:".

Sometimes you need to slightly modify patches you receive in order to
merge them, because the code is not exactly the same in your tree and
the submitters'. If you stick strictly to rule (c), you should ask the
submitter to rediff, but this is a totally counter-productive waste of
time and energy. Rule (b) allows you to adjust the code, but then it
is very impolite to change one submitter's code and make him endorse
your bugs. To solve this problem, it is recommended that you add a
line between the last Signed-off-by header and yours, indicating the
nature of your changes. While there is nothing mandatory about this,
it seems like prepending the description with your mail and/or name,
all enclosed in square brackets, is noticeable enough to make it
obvious that you are responsible for last-minute changes. Example :

  Signed-off-by: Random J Developer <random@developer.example.org>
  [lucky@maintainer.example.org: struct foo moved from foo.c to foo.h]
  Signed-off-by: Lucky K Maintainer <lucky@maintainer.example.org>