Python docs is incorrect.

[Carreau]

It mixes deploying with buildpacks and docker.

Flyctl launch will create a docker file in CWD which

1. is wrong and try to run demo.wgi, and call manage.py that does not exists.
2. the docs mention buildpack so I guess fly.toml needs a

[build]
  builder = "paketobuildpacks/builder"
  buildpacks = ["gcr.io/paketo-buildpacks/python"]