Create initial provider

[tptee]

Creates the initial serverless_deployment resource which wraps the Serverless CLI. Only runs sls deploy when the contents of serverless.yml and the package ZIP archive contents change. Assumes that users run packaging out-of-band.

Hoping to split docs and niceties into another PR while we dogfood the provider.

Example:

resource "serverless_deployment" "example" {
  config_path         = abspath("./")
  serverless_bin_path = abspath("./node_modules/.bin/serverless")
  # Relative to config path
  package_dir         = ".terraform-serverless"
  stage               = "sandbox"
}

To test, you need access to the Formidable account set up with aws-vault. Run aws-vault exec formidable then make testacc.

@dmmulroy I'd love your input here since you have some experience with Go!

[tptee]

Ready for another look!

[ryan-roemer]

Can we get some comments as to what we're hashing, why, and what scenarios we're trying to cache / skip over?

[ryan-roemer]

Do we want to make this not required and instead default to CWD?

[tptee]

My gut is that would be more error-prone, as I haven't seen a project share Terraform modules and serverless.yml/node_modules in the same CWD before.

[tptee]

Oh you know what, might be nice to default it to the node_modules in the config_dir!

[tptee]

Made the above the default!

[ryan-roemer]

Looking great so far! In addition to my current review pass comments, can we maybe get a CONTRIBUTING.md document that has sections for:

• Development: Localdev installation, running the tests, running lint, doing a deploy from example (with installation, etc. instructions)
• Release: Since git tags should cause a full release, maybe just giving guidance for that via straight git commands since we don't have a root package.json for scripts? (Or something of your choosing).

Here's https://github.com/FormidableLabs/terraform-aws-serverless/blob/master/CONTRIBUTING.md for reference which has some of what you may want if that's useful!

[tptee]

Should be ready for another pass!

[ryan-roemer]

Everything outside of the go code (which I'm not familiar with) looks good!

I think we do need a README.md with full integration instructions as this is a departure from normal SLS workflows and such, particularly for the packaging part if you have to somehow do that outside terraform or can do this with additional config within this provider because that's likely going to be a large stumbling block for our users.

[tptee]

Added README!

[dmmulroy]

Only skimmed the Go, but lgtm