Fixing MW sign check on startup

missilewars-plugin/src/main/java/de/butzlabben/missilewars/game/signs/SignRepository.java

@@ -108,6 +108,6 @@ public class SignRepository {
     }
 
     public List<MWSign> getSigns(Game game) {
-        return signs.stream().filter(s -> s.getLobby().equals(game.getArena().getName())).collect(Collectors.toList());
+        return signs.stream().filter(s -> s.getLobby().equals(game.getLobby().getName())).collect(Collectors.toList());
     }
 }