def renumber(map)
      @members.each_with_index do |pnum, index|
        raise "player number #{pnum} not found in renumbering hash" unless map[pnum]
        @members[index] = map[pnum]
      end
      self
    end
def renumber(map)
      @members.each_with_index do |pnum, index|
        raise "player number #{pnum} not found in renumbering hash" unless map[pnum]
        @members[index] = map[pnum]
      end
      self
    end
Renumber the players according to the supplied hash. Return self.