Move cli.py to __main__.py to allow for python -m package

[znd4]

Hello! I love this template. While using it at a pycon tutorial, I noticed that it doesn't have a __main__.py, so it's not possible to run python -m package_name. I thought I'd submit a PR to make that possible.

Let me know what i'm missing, or if this is totally off-base. And thanks again for the awesome template :)

[PsiACE]

Nice to see you working on it. I'll check on it later.

[PsiACE]

I thought we could do something like flask, just add one __main__.py file.
Please let me know if there are any intuitive benefits to removing the cli.py.

[znd4]

Hmm. I think my intuition was that it's simpler to just have __main__.py, but I think I can see a few more benefits for the approach that flask uses.

1. It might make sense to have some code in cli.py that you'd actually want to import. (i.e. mypackage.cli). (Now that I think about it, I've actually ran into an issue with this in the past, where I had some code in my __main__.py file that I had to pull out into a separate module so that I could import it somewhere else. If I had put all of that into a cli.py file from the beginning, I never would've had to do that.
2. cli.py just seems like a more descriptive name than __main__.py -- I still get confused by how dunder things work sometimes.

Also, it doesn't seem like that big of a deal to just add one more file, especially considering how many files tend to end up in a python package project

Would you like me to refactor this PR to use an approach more like flask's?

[PsiACE]

Yeah, I think that's better. I'd be happy to merge it if you refactor it.