The much-awaited Roxy’s Grilled Cheese truck has firmed up an opening date for its Allston brick-and-mortar (485 Cambridge St. at Brighton Avenue). The restaurant is slated to open on May 19, says owner James DiSabatino. “It’s our food truck on overdrive,” he says. Expect burgers, poutine, beer and wine, and, of course, grilled cheese (in both gluten-free and vegan permutations). Roxy’s will be open seven days a week, from 11 a.m. until 11 p.m.