The Highlander Cafe, an outlet for Somerville’s students studying culinary arts and restaurant management, opened for business on Thursday, the School Department said. Open to the public between 11:15 a.m. and 1 p.m. Wednesday through Friday, the cafe is in Somerville High School next to the gymnasium. It gives valuable experience to teens looking to enter the food and service industries. Menus are posted online every week at somerville.k12.ma.us/cafe.