Add alternative merge type and merge notes to merge requests
This adds two minor, optional features to merge requests that were necessary for our workflow and might be useful for others.
"merge_ff_only": Instead of the default "pull --no-ff" that creates a merge commit, do "merge --ff-only" on merge requests. This means the resulting history on the destination branch will be linear, and also that non-ff merge requests will be marked as unmergeable until rebased.
"add_merge_notes": With the above strategy we won't get the merge commit indicating who did the merge. Instead, this adds notes to refs/notes/merge to each merged commit with the text "Merge-By: Full Name email@example.com" which can be pulled and examined after the fact.
I'll be keeping this as a local patch either way, so if there's no interest from the community for these features, feel free to close the pull request.