initial group log

src/main/java/mops/gruppen2/domain/event/CreateGroupEvent.java

@@ -39,6 +39,11 @@ public class CreateGroupEvent extends Event {
         log.trace("\t\t\t\t\tNeue Gruppe: {}", group.toString());
     }
 
+    @Override
+    public String format() {
+        return "Gruppe erstellt.";
+    }
+
     @Override
     public String type() {
         return EventType.CREATEGROUP.toString();