Hello Mic:
copy the necessary jar files and resources inside this Dockerfile.
Next you need to have docker-compose.yml into root of your project. In this docker.compose.yml you need two services viz. hapi/fhir and your application. Typically you need to mention image, ports, environment and networks. Then your application service builds using your Dockerfile specified in the context.
Also make sure, your app and hapi/fhir are properly configured to communicate with each other viz. via auth token etc.
Thanks