dokku is also meant to build a custom image on deploy : rather than using heroku's buildpacks, you can put a Dockerfile at the root of your project and it will be used instead.
So basically, you could put a Dockerfile file container just FROM and MAINTAINER, referring the image you want to use in the FROM, and dokku will download and execute it on `git push` (provided it can access to the image repository).
So basically, you could put a Dockerfile file container just FROM and MAINTAINER, referring the image you want to use in the FROM, and dokku will download and execute it on `git push` (provided it can access to the image repository).