A new Grubhub restaurant delivery promotion called “Supper for Support” isn’t quite so supportive as it sounds. The deal, a $10 discount to diners on Grubhub orders of $30 or more from 5 p.m. to 9 p.m daily, is advertised to customers as a way to “save while supporting the restaurants you love,” a means of financially fueling the many food businesses across the country that now rely solely on delivery and pickup orders, with their dining rooms closed by