Property ref

[erdnaxeli]

This PR based on the work done on #23. It allows to use a ref in a property object, as defined by the OpenAPI v3 spec.

builder.add(Swagger::Object.new("User", "object"))
builder.add(
  Swagger::Object.new(
    "Post",
    "object"
    [
      Swagger::Property("content"),
      Swagger::Property("author", "object", ref: "User"),
    ],
)

I think it is obvious that I am duplicating the code that was in Swagger::Objects::Schema to Swagger::Objects::Property. Actually in the OpenAPI v3 spec they are both the same. The properties dict is Hash(String, Schema).

So I would like to propose to merge those two types. For the user facing API we can keep the Swagger::Object and Swagger::Property distinction, but for the OpenAPI generation I don't think it brings any advantage.

[icyleaf]

CI failed because the code was not formatted. please run the command below and commit:

crystal tool format src
crystal tool format spec