try to make naming more consistent

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

@@ -5,7 +5,7 @@ import lombok.Getter;
 @Getter
 public class DeleteUserEvent extends Event{
 
-    public DeleteUserEvent(long id, long gruppe_id, String user_id) {
-        super(id, gruppe_id, user_id);
+    public DeleteUserEvent(long event_id, long group_id, String user_id) {
+        super(event_id, group_id, user_id);
     }
 }