composer.json

 {
    "name": "backdrop-docker/backdrop",
     "description": "Run Backdrop using Docker containers.",
     "minimum-stability": "dev",
     "repositories": [
        {
            "type": "package",
            "package": {
                "name": "tabroughton/backdrop",
                "version": "1.13.3",
                "dist": {
                    "url": "https://github.com/backdrop/backdrop/archive/1.13.3.zip",
                    "type": "zip"
                }
            }
        },
        {
            "type": "package",
            "package": {
                "name": "tabroughton/civicrm",
                "version": "5.16.4",
                "dist": {
                    "url": "https://download.civicrm.org/civicrm-5.16.4-backdrop.tar.gz",
                    "type": "tar"
                }
            }
        },
        {
            "type": "package",
            "package": {
                "name": "polydigital/civicrm-backdrop",
                "version": "dev-master",
                "source": {
		    "url": "https://github.com/polydigital/civicrm-backdrop.git",
                    "type": "git",
		    "reference":"df6c1eee93b920f35318f38ebac2e584f00f2799"
                }
            }
        },
        {
            "type": "package",
            "package": {
                "name": "backdrop-contrib/drush",
                "version": "dev-master",
                "source": {
		    "url": "https://github.com/backdrop-contrib/drush.git",
                    "type": "git",
		    "reference":"1d4b9ba7dcbe6f8d84ca38d34283a5d18346af6d"
                }
            }
        }
     ],
    "require": {
        "tabroughton/backdrop": "1.13.3.*",
        "backdrop-contrib/drush": "dev-master",
        "drush/drush": "8.3.0",
	"tabroughton/civicrm": "5.16.4.*",
	"polydigital/civicrm-backdrop": "dev-master"
    }
}