code: def data_only_container(name, volumes):
      
      info = inspect_container(name)
      if info:
          return
      c = _get_docker().create_container(
          name=name,
          image='datacats/postgres',  # any image will do
          command='true',
          volumes=volumes,
          detach=True)
      return c
docs: create "data-only container" if it doesn't already exist.
  
      We'd like to avoid these, but postgres + boot2docker make
      it difficult, see issue #5