func (a *DataStreamService) Update(dataStream *models.DataStream) error {
	revel.INFO.Println("updating data stream", dataStream.ToString())
	count, err := persistence.Dbm.Update(dataStream)
	checkErr(err, "data stream not updated "+dataStream.ToString())
	if count == 1 {
		return nil
	}
	return err
}
func (a *DataStreamService) Save(dataStream *models.DataStream) *models.DataStream {
	revel.INFO.Println("saving data stream", dataStream.ToString())
	persistence.Dbm.Insert(dataStream)
	return dataStream
}