Merge pull request #863 from cybozu-go/force-dco

docs: document DCO sign-off policy

Author: yamatcha

DEVELOP.md

@@ -17,6 +17,12 @@ This project uses [aqua](https://aquaproj.github.io/) to manage development tool
 
 Once aqua is installed, the required development tools will be automatically installed when you run make commands.
 
+## Commit sign-off
+
+All commits must be signed off per the [Developer Certificate of Origin](https://developercertificate.org/).
+Run `git commit -s` (or configure your Git client accordingly) so each commit carries a `Signed-off-by` line.
+Pull requests without signed-off commits will be rejected by our checks.
+
 ## Running tests
 
 MOCO has the following 4 kinds of tests:

README.md

@@ -116,6 +116,10 @@ See https://cybozu-go.github.io/moco/
 
 [`examples`](examples/) directory contains example MySQLCluster manifests.
 
+## Contributing
+
+We require all commits to comply with the [Developer Certificate of Origin](https://developercertificate.org/). Use `git commit -s` (or configure your Git client to add a `Signed-off-by` trailer) to sign off every commit before opening a pull request. Pull requests without the trailer will not pass our checks.
+
 ## Docker images
 
 Docker images are available on [ghcr.io/cybozu-go/moco](https://github.com/orgs/cybozu-go/packages/container/package/moco).