text: AppService.service('CarGroup', function($q, WilddogNotifyBaseURL) {
      this.list = [];
  
      this.getGroupList = function(username) {
          console.log("get group list ref: ", WilddogNotifyBaseURL + username + '/cargroup');
          var carGroupRef = new Wilddog(WilddogNotifyBaseURL + username + '/cargroup');
          var deferred = $q.defer();
  
          carGroupRef.once('value', function(snapshot) {
              this.list = snapshot.val();
              deferred.resolve(this.list);
          }, function(err) {
              deferred.reject(err);
          });
  
          return deferred.promise;
      }
  });
  