RFC: Optional flags for opt-in features?

[j6k4m8]

It would be nice to be able to add --tests to include a tests/ submodule, or --poetry to add

[tool.poetry]
name = "foobar"
version = "1.2.3"
description  = "bar fooer"
authors = ["Baz Lightyax"]

to the pyproject.toml.

Perhaps the right home for these sorts of additions is in a plugin registry?

Other thoughts:

• black: we currently include a [tool.black] section, but not the byproducts of running

  poetry add --dev black --allow-prereleases
  

• flake: A plugin system might be a good place to give a user the option to select defaults

[mlw214]

I'm very much envision this tool to be based around pip-tools (hence the requirements directory), though I might be up for plugins. I'd have to think about how that would look.