Get app starting on heroku

[Br3nda]

Not sure why the dockerfile wasn't starting the entry point on heroku -- so I made it simpler. Just a simple shell script
then put the longer incantation to start it in that script. I added the $PORT variable. Heroku sets this to tell your app what to start on.

I've also added to the README

[Br3nda]

Thank you to @sarafalamaki for getting git submodules working for me

[Br3nda]

this is deployed happily to https://testrules.herokuapp.com/spec

[Br3nda]

ooo one more thing. I need to do this using the heroku cli

heroku stack:set container --app testrules

[sarafalamaki]

Thanks so much for this @Br3nda! I'm not sure why the test is not passing. Is it a permission thing?

[Br3nda]

@sarafalamaki there's a step with this;

    - uses: docker/build-push-action@v1
      with:
        username: ${{ secrets.DOCKER_USERNAME }}
        password: ${{ secrets.DOCKER_PASSWORD }}
        registry: ${{ secrets.DOCKER_REGISTRY }}
        repository: openfisca_nsw_api
        tags: latest
        dockerfile: openfisca_nsw_api.Dockerfile

I'm not sure why you're doing this on every push and every pull request.

Should we instead change it to only push to the docker registry when it's a merge into our main branch?

[Br3nda]

i think you want to build it on every PR and push, but only publish it if it's been accepted into the master branch.