Story 3 and Story 4 finished

src/main/java/de/etecture/ga/model/Appointment.java

@@ -20,6 +20,9 @@ public class Appointment {
 	@Column("GARAGE_ID")
 	private AggregateReference<Garage, Long> garageId;
 	
+	@Column("SERVICE_ID")
+	private AggregateReference<MDService, Long> serviceId;
+	
 	private String serviceCode;
 	
 	private String serviceName;