update release process doc (#398)

docs/contributing/release-process.md

@@ -12,11 +12,51 @@ The `main` tag points to the latest commit on the main branch.
 If you push a tag `vX.Y.Z` to the repository, the Docker image with the tag `vX.Y.Z`
 is built and pushed to Docker Hub. Afterwards, the `latest` tag is updated to point to the new version.
 
+Use the commands below to create a new release.
+
+Check the latest version tag:
+
+```sh
+git pull --tags
+git tag -l | grep -E "^v[0-9]" | sort -t "." -k1,1n -k2,2n -k3,3n
+```
+
+This may show `v0.14.0`. If that's the case then tag the next version with
+`v0.15.0` by running:
+
+```sh
+git checkout main
+git pull origin main
+git tag v0.15.0
+git push --tags
+```
+
+You can go to the GitHub action page and see that a new action has been triggered. This action to build and publish needs to succeed.
+
+Afterwards you can pull the new image:
+
+```sh
+docker pull substratusai/kubeai:v0.15.0
+```
+
 ## Helm Chart
 The Helm chart only gets released when a git tag is pushed to the repository with
 the format `helm-v*`.
 
 The appVersion in the Helm chart does not have to point to the latest released version. This allows us to first publish a new version of the Docker image without updating the Helm chart. The Helm chart is updated when we are ready to release a new version.
 
 This is important when a new appVersion isn't compatible with the current Helm chart.
-In those cases, we can first merge the PR, thoroughly test, release new container image, and then in a separate PR update the Helm chart and the appVersion.
+In those cases, we can first merge the PR, thoroughly test, release new container image, and then in a separate PR update the Helm chart and the appVersion.
+
+Steps to release a new version:
+1. Create a new PR and update the helm chart versions and appVersion.
+2. Merge the PR into main.
+3. Create a new tag from main branch with the format `helm-vX.Y.Z`. Make sure to match the tag to the helm chart version. Push the tag.
+
+After merging to main:
+
+```sh
+git pull origin main
+git tag helm-v0.12.0
+git push --tags
+```