code: function registerApi(isApp, apiObject) {
  
    if (isApp) {
      return function (req, res, next) {
        res.__api = apiObject;
        return next();
      };
    };
    
    return function (req, res, next) {
      res.__modelAPI = apiObject;
      return next();
    };
  }
docs: registerApi - the factory for middleware that registers api in response object
  
  @param  {ModelAPIRouter|ModelAPIExpress} apiObject the ModelAPIRouter or ModelAPIRouter
  @return {Function}           description