`docker-compose.yml` assumes that the `godbledger` server image has been built

[davidalpert]

I recently cloned this repo on a new macbook and ran into the following error When running make docker-start:

Pulling app (godbledger:latest)...
ERROR: The image for the service you're trying to recreate has been removed. If you continue, volume data could be lost. Consider backing up your data before continuing.

Continue with the new image? [yN]y
Pulling app (godbledger:latest)...
ERROR: pull access denied for godbledger, repository does not exist or may require 'docker login': denied: requested access to the resource is denied

After some investigation, it appears that:

1. docker-compose.yml references the godbledger image
2. there is no dockerfile in this repo for the godbledger image

I believe that this repo assumes that the build-docker target has been successfully run in the core https://github.com/darcys22/godbledger repo (step 1 from https://github.com/darcys22/godbledger#running-in-docker) before running the make docker-start target in this repo.

I suggest updating the README.md file in this repo with some additional instructions either to run make docker-build in the core repo first or to share this error message and remediation steps in README.md under a new Known Issues section.