I have a set of documentation for my company\'s API, based on the excellent Slate framework from TripIt. Per instructions, I forked their repo and proceeded to customize it.
Your other developers seem to have forked TripIt
's repository, so that is the source/parent of their work.
In fact, if you open your own repository, you will see it hasn't been forked at all (the fork count is 0).
When they issue a merge request, by default github shows that repository as source, and so the pull request isn't sent to you.
The simplest workaround in this case is to ask your dev's to fork your repository, and work on it.