Walmart is pushing into restaurant delivery . Its first goal: Getting you a sub sandwich on demand. The big box retailer has been delivering meals from Subway restaurants located in Walmart stores for about a month, said Tracy Poulliot, vice president of e-commerce and marketing at Walmart. The retailer aims to have the delivery option live at all 1,400 Subways within Walmart stores by late July. Business Insider first reported that Walmart was testing restaurant delivery . Customers can place