Spec generation doesn't honour the ",string" JSON struct tag

[neilgarb]

Problem statement

I have a field in a response struct which specifies that it's encoded as a string when marshalled to JSON.

// swagger:model
type Foo struct {
    Bar int64 `json:"bar,string"`
}

When I generate the spec for Foo, the type of Bar is integer, when it should in fact be string.

Proposed solution

In parseJSONTag(), also return a boolean indicating that the field has the ",string" directive. When the field's type is determined, override it with type:string and format: if the directive is present.

Swagger specification

2.0

Steps to reproduce

N/A

Environment

swagger version: 2.0
go version: 1.10.1
OS: macOS 10.12.6

[casualjim]

fixed by #1511