chore(docs): add job container dind docs (#44)

Reviewed-on: https://gitea.com/gitea/helm-actions/pulls/44
Reviewed-by: DaanSelen <daanselen@noreply.gitea.com>
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-by: Markus Pesch <volker.raschek@noreply.gitea.com>
Co-authored-by: Christopher Homberger <christopher.homberger@web.de>
Co-committed-by: Christopher Homberger <christopher.homberger@web.de>

README.md

@@ -6,6 +6,10 @@ The parameters which can be used to customize the deployment are described below
 
 If you want to propose a new feature or mechanism, submit an [issue here](https://gitea.com/gitea/helm-actions/issues).
 
+## Docs
+
+[Docs](./docs/README.md)
+
 ## Rootless Defaults
 
 If `.Values.image.rootless: true`, then the following will occur. In case you use `.Values.image.fullOverride`, check that this works in your image:

docs/README.md

@@ -0,0 +1,3 @@
+# Gitea Actions Helm Chart Docs
+
+- [Share dind with job container](share-dind-with-job-container.md)

docs/share-dind-with-job-container.md

@@ -0,0 +1,36 @@
+# Share dind with job container
+
+You can weaken isolation and allow jobs to call docker commands.
+
+## Limitations
+
+- Docker bind mounts like `-v /path/on/self/container:/path/to/new/container` do not work, because they are going to mount the path from the dind container
+- Docker port expose to local host `-e 80:8080` is not going to work
+
+## Example Values
+
+```yaml
+enabled: true
+statefulset:
+  actRunner:
+    # See full example here: https://gitea.com/gitea/act_runner/src/branch/main/internal/pkg/config/config.example.yaml
+    config: |
+      log:
+        level: debug
+      cache:
+        enabled: false
+      container:
+        valid_volumes:
+        - /var/run/docker.sock
+        options: -v /var/run/docker.sock:/var/run/docker.sock
+
+## Specify an existing token secret
+##
+existingSecret: "runner-token2"
+existingSecretKey: "token"
+
+## Specify the root URL of the Gitea instance
+giteaRootURL: "http://192.168.1.2:3000"
+```
+
+Now you can run docker commands inside your jobs.