I am actively trying to keep up with pull-requests from people who are forking the repos to make changes, and I'm trying also to give credit in the readme etc.
-Oliver
One idea that solves this problem I have seen earlier was having an AUTHORS file in the project root directory (with name and email address). This way the authors themselves were referenced in the readme/credits only indirectly.
Perhaps the file was sorted alphabetically. One could easily see in git who does most of the work (where credit is due) anyway.
Then everyone making a pull request was required to add herself/himself to the AUTHORS file for their first pull request. Problem solved.