Mayor Michael R. Bloomberg announced that a gas-rationing system he ordered put in place two weeks ago would end on Saturday. The Mayor introduced the rationing for city drivers for the first time since the 1970s on Nov. 9, after Hurricane Sandy crippled the regionâ€™s fuel-supply network and resulted in lines that were hours long at stations in the city. The cityâ€™s plan was put in place on the same day that a gas-rationing plan was started on Long Island. New Jersey was the first to impose rationing in several counties, and it lasted there for 10 days. On Long Island, officials in Nassau and Suffolk Counties ended gas rationing last Friday.