Make port configurable for MySQL (other ports too?)

[pjedrzejewski]

ERROR: for mysql Cannot start service mysql: driver failed programming external connectivity on endpoint docker_mysql_1 (ad2d3430d8c5c83aba9633c20b10c4ebb7df8090bf6828b86072401e67c08173): Error starting userland proxy: Bind for 127.0.0.1:3306 failed: port is already allocated
ERROR: Encountered errors while bringing up the project."

[adepretis]

You would have to edit docker-compose.yml for that. There is the possibility to use docker-compose.local.yml (see PR #12) but docker-compose merges YAML arrays and does not replace them (there is an open PR for that - docker/compose#3939).

We could use ENV variables to achieve this, e.g.:

$(eval $(call defw,MYSQL_EXPOSE_PORT=

make MYSQL_EXPOSE_PORT=4711 up

and

```yaml
services:
  mysql:
    ports:
      - ${MYSQL_EXPOSE_PORT}:3306

but I would prefer to keep the amount of ENV vars for controlling the whole development environment at a minimum and not drown in ENVs ;-)

Changing/Extending the initial configuration including ports has been documented in the README.md, which I think is enough for now. What do you think?

I also just changed the default exposed port from 3306 to 3606 (see b27fec4)

[pjedrzejewski]

Info in README is enough and I agree we should avoid adding 10s of ENV vars. Closing this, thanks Andreas!