Retailers reinforced their ranks last month, gaining 12,900 jobs, according to a report from the National Retail Federation. The increase in November followed a loss of 10,300 jobs in October and an increase of 10,600 positions in September. Retailers’ annual hiring of temporary holiday workers is on track to reach NRF’s predicted total of 500,000 to 550,000 positions. “This was one of the strongest gains we’ve seen all year,” NRF Chief Economist Jack Kleinhenz said in the report.