Overriding entrypoint and command in docker-compose.yml

@dmaze I actually have to use multiple virtualenvs as my project has multiple python apps with different dependencies and I shouldn’t allow them to conflict with each other.

Interestingly, I came across pipenv on a hacker news submission of mine last night, and created a nice Dockerfile that bootstraps Debian with pyenv, a custom python runtime, and pipenv for a usecase similar to mine.

@think the init file solution looks like a potential sol’n. Thanks!