init method
Implementation
@override
Future<void> init(SchemaMetaData smd, SchemaMetaData smdSys, DbTransaction transaction) async {
await super.init(smd, smdSys, transaction);
defaultWaterState = WaterState.SERVER_APPROVED;
validWaterStates = {WaterState.SERVER_APPROVED, WaterState.SERVER_PENDING, WaterState.SERVER_REJECTED};
}