code: func (r *Request) Payload(v interface{}) bool {
  	if r.Req.Body == nil {
  		r.Fail(Bad(nil, "no JSON input payload present in request"))
  		return false
  	}
  
  	if err := json.NewDecoder(r.Req.Body).Decode(v); err != nil && err != io.EOF {
  		r.Fail(Bad(err, "invalid JSON input payload present in request"))
  		return false
  	}
  
  	return true
  }
docs: //Payload unmarshals the JSON body of this request into the given interface.
  // Returns true if successful and false otherwise.