Add a contributor without creating an issue / comment

**Is your feature request related to a problem? Please describe.**

A new backer joined [nock’s open collective](https://opencollective.com/nock), there are is no issue or pull request on the repository I could comment on.

**Describe the solution you'd like**

I wonder if the app could provide a custom UI to add a new contributor. E.g. there could be something like https://app.allcontributors.org/add-contributor with an OAuth authentication flow and a form that matches the current comment syntax to add a new contributor

**Describe alternatives you've considered**

I’ve created a new issue which is a decent alternative: I created one here:
https://github.com/nock/nock/issues/1461

One thing that would be cool is if the pull request created for the new issue would include `closes #123`

I added it manually now

https://github.com/nock/nock/pull/1462