Add policyfile generator

[danielsdeleo]

Generates a policyfile with comments about usage and link to the POLICYFILE_README

/cc @opscode/client-engineers

[sersut]

Should we add other source options here in commented form as well?

[danielsdeleo]

I'm not sure. On the one hand, we don't have much documentation yet, but I also want to keep the example stuff to a minimum. Maybe we should plan to add a "usage" section to the POLICYFILE_README instead?

[sersut]

Yeah you're right. I was thinking to have them to raise curiosity of the new users but at the same time it makes it more complex too. Maybe we can add :chef_server when we have the ability to use it as private supermarket.

[danielsdeleo]

Yup, :chef_server source was always part of the plan, just waiting on the /universe endpoint so people can use it as the default source.

[sersut]

In #150 @jonlives used "example" as the name of the initial thing we're generating. Maybe we can use "example" or "example_app" instead of "my_app" for slightly better coherence.

[sersut]

Other than 2 minor things 👍

[tyler-ball]

Ah, so THIS is the right way to include shared options. Good to know!

[danielsdeleo]

@tyler-ball it's the best we have, I don't know how you could really improve it without rewriting mixlib-cli. You can make it more magical if you include a module and then use the module's Module.included callback hook, but IMO it's more complicated for more code so not a big help.

[tyler-ball]

👍