public void DeleteButton_Click()
{
foreach (TblThemes theme in TeacherHelper.ThemesOfCourse(course))
{
ServerModel.DB.Delete <TblPermissions>(TeacherHelper.AllPermissionsForTheme(theme));
}
ServerModel.DB.Delete <TblPermissions>(TeacherHelper.AllPermissionsForCourse(course));
CourseCleaner.DeleteCourse(course.ID);
Redirect(BackUrl);
}