public void addTaskParticipatingUser(String taskId, String userId, String participation) {
commandService.execute(new AddParticipationCmd(taskId, null, userId, null, participation));
}
public void addTaskParticipatingGroup(String taskId, String groupId, String participation) {
commandService.execute(new AddParticipationCmd(taskId, null, null, groupId, participation));
}