OpenAPI Support

Hey! I see you've got OpenAPI on the roadmap, I'm just putting this issue here so I can get an update when it's done. 

I'll be happy to talk to you about getting up on https://openapi.tools and other directories so our community can find you, and maybe can write a few blog posts so the community are even more aware of what you're up to here. It looks interesting. 🙌🏻 