code: func (api *API) CreateRailgun(name string) (Railgun, error) {
  	uri := api.userBaseURL("") + "/railguns"
  	params := struct {
  		Name string `json:"name"`
  	}{
  		Name: name,
  	}
  	res, err := api.makeRequest("POST", uri, params)
  	if err != nil {
  		return Railgun{}, errors.Wrap(err, errMakeRequestError)
  	}
  	var r railgunResponse
  	if err := json.Unmarshal(res, &r); err != nil {
  		return Railgun{}, errors.Wrap(err, errUnmarshalError)
  	}
  	return r.Result, nil
  }
docs: // CreateRailgun creates a new Railgun.
  //
  // API reference: https://api.cloudflare.com/#railgun-create-railgun