Add Rust Working Group (bp #893) (bp #1015)

[mergify]

This is an automated backport of pull request #1015 done by Mergify

Cherry-pick of 6c121ac has failed:

On branch mergify/bp/dashing/pr-1015
Your branch is up to date with 'origin/dashing'.

You are currently cherry-picking commit 6c121ac.
  (all conflicts fixed: run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

nothing to commit, working tree clean

To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

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