code: function (appIdOrSlug) {
      var path;
      if (appIdOrSlug) {
        path = this.constructPath(constants.APPS, appIdOrSlug);
        return this.Core.DELETE(path);
      } else {
        return this.rejectRequest('Bad Request: An app id or slug is required.');
      }
    }
docs: Delete an app
  @param  {String|Integer} appIdOrSlug A Robin app identifier or slug
  @return {Function}                   A Promise