dumb max

gistfile1.rb

def best_team(team_map)
  best = nil
  team_map.each {|x,team| if best == nil || team.win_loss_ratio() > best.win_loss_ratio() 
                            best = team
                          end
  }
  best
end

team_map.map(&:win_loss_ratio).max

or

team_map.map { |t| t.win_loss_ratio }.max