Docker Port Forwarding
I believe the problem you have is that EXPOSE only makes the ports available between containers... not to the host system. See docs here:
https://docs.docker.com/reference/builder/#expose
You need to "publish" the port via the -p flag for docker run command:
https://docs.docker.com/reference/run/#expose-incoming-ports
There is a similar distinction in Fig, if you were using it, between expose and ports directives in the fig.yml file.