Support pre-processed community contracts documentation with API Refe…

…rence (#421)

Co-authored-by: Francisco Giordano <fg@frang.io>

README.md

@@ -16,3 +16,16 @@ To show it in the sidebar, add the `name` from the repo's `antora.yml` in
 inside the [`icons folder`](./ui/theme/images/icons) matching the name.
 
 Finally, add an entry for it inside the [`model.yml`](./ui/preview/model.yml) file, for UI development purposes.
+
+### Pre-processing
+
+The contents of each repository under `sources` in `playbook.yml` are used as-is
+with no pre-processing. If the repository requires a pre-processing step, it must
+be done in the CI of that repository and the results pushed to a branch (e.g., `docs`).
+This branch should then be specified as the source in `playbook.yml` instead of the
+source branch (e.g., `HEAD`).
+
+An example of a CI Github Action that pre-processes the `master` branch and
+pushes the result to the `docs-v*` branch can be found in the OpenZeppelin
+Contracts [docs workflow](https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/.github/workflows/docs.yml).
+This workflow creates an automated API reference for the Contracts library.

playbook.yml

@@ -28,7 +28,7 @@ content:
       start_path: packages/lib/docs
 
     - url: https://github.com/OpenZeppelin/openzeppelin-community-contracts
-      branches: HEAD
+      branches: docs-v*
       start_path: docs
 
     - url: https://github.com/OpenZeppelin/openzeppelin-upgrades