box-o-sand/rails/map-mash/app/models/mash_tournament_round.rb

class MashTournamentRound < ActiveRecord::Base
  belongs_to :tournament, :class_name => 'MashTournament'
  has_many :mashes

  def self.for_round(tournament, round_number)
    self.find_by_mash_tournament_id_and_number(tournament, round_number)
  end

  def done?
    winners = []
    self.mashes.collect do |mash|
      winners << mash.winner_id
    end
    !winners.include?(nil)
  end
end