document github support

README.md

@@ -6,3 +6,23 @@ For an example checkout the [example](./examples/default.nix) and the module
 descriptions for [master](./nix/master.nix) and [worker](./nix/worker.nix).
 
 This project is still in early stage and many APIs might change over time.
+
+## Github
+
+We currently primarly support Github as a platform but we are also looking into
+supporting other CIs such as gitea.
+
+Buildbot requires a GitHub app, to allow login for GitHub users to its
+dashboard.
+
+Furthermore buildbot requires a github token with the following permissions:
+
+- `admin:repo_hook`, `public_repo`, `repo:status`
+
+For github organisations it's recommend to create an additional GitHub user for
+that.
+
+## Real-worlds deployments
+
+- [Nix-community infra](https://github.com/nix-community/infra/tree/master/modules/nixos)
+- [Mic92's dotfiles](https://github.com/Mic92/dotfiles/blob/main/nixos/eve/modules/buildbot.nix)