Fixing AirplaneType assignment to be persistent

core/src/main/java/cz/muni/fi/pa165/core/facade/airplane/AirplaneFacadeImpl.java

@@ -84,6 +84,7 @@ public class AirplaneFacadeImpl implements AirplaneFacade<Long> {
 
         if (airplaneEntity.isPresent() && airplaneTypeEntity.isPresent()) {
             airplaneEntity.get().setType(null);
+            airplaneService.save(airplaneEntity.get());
         }
     }