Deployment Manager offers a simple and standardized workflow to automate deployments to production. We strongly recommend you not to alter the case types generated behind the scenes since it may break existing functionality and it will make it significantly more difficult to upgrade to newer versions in the future.
We have on our roadmap an ability to add more stages to your model.
If you want to add a custom task, our custom task infrastructure allows you to create tasks specific to your DevOps needs. Please reach out to us in order to learn more about it.