Update docker-compose.yml

[Hiiiij]

updating the path; Adding Ruby command to run a local server

[Hiiiij]

Adding Ruby command to.run a local server

[biggianteye]

Some of the conversation following this comment is relevant: https://github.com/codebar/planner/pull/1882#issuecomment-2094351062

[matyikriszta]

Thanks for this PR @Hiiiij . I'm closing it because we deliberately want to stick to the current approach of starting a container and running a server in the container being two distinct steps. Making developers run a command to start the server lets them see the server logs immediately, while running the server as part of the container startup makes the server logs harder to find. We are going to update the README to make this clearer.