It has been three years since General Motors Corp., like other Big Three automakers, committed to do 5% of its business with minority-owned automotive suppliers. The No.1 automaker is keeping that pledge by fostering growth at Vitec, a fuel tank producer that recently celebrated its third anniversary as a minority operation. The company has 250 employees producing 800,000 plastic fuel tanks annually in a new plant in southwest Detroit's Empowerment Zone. “It is our intention to grow your business,” Bo Andersson, executive in charge of worldwide purchasing at GM, told the company in a luncheon speech. GM is Vitec's biggest customer.