Enable your PHP project to deploy to Heroku via Container Registry.
$ composer require --dev ttskch/php-heroku-docker-applyer:@dev
$ bin/php-heroku-docker-applyer <appname> # your Heroku app nameAfter this, following files are hard copied into your project. This library is just for copying files so you can composer-remove this library after this step.
.
├── .circleci
│   └── config.yml
├── .travis.yml
└── DockerfileNow you can deploy your project to Heroku by heroku container:login && heroku container:push web.
You can also deploy via CircleCI or Travis CI. For this, add following two environment variables to your CI platform.
| var | value | 
|---|---|
DOCKER_USERNAME | 
your Heroku email address | 
DOCKER_PASSWORD | 
your Heroku API key | 
See also Heroku document.
Now you can deploy your project to Heroku via CircleCI or Travis CI. Enjoy!