private void deleteStage(TblStages stage)
{
foreach (TblThemes theme in TeacherHelper.ThemesOfStage(stage))
{
deleteTheme(theme, stage);
}
//remove permissions
ServerModel.DB.Delete <TblPermissions>(TeacherHelper.AllPermissionsForStage(stage));
ServerModel.DB.Delete <TblStages>(stage.ID);
}