Indoor arena football is coming back to Roanoke. A new indoor league will include Roanoke as one of its 12 teams. The National Gridiron League will begin play next spring, with the Virginia Iron Horses based at the Berglund Center. The league is slated to be a minor league alternative to the N.F.L. and a place for college graduates to extexnds their playing careers. Roanoke City Mayor Sherman Lea was on hand for the announcement this morning: