class ActiveGenie::Ranking::EloRound

def call
  ActiveGenie::Logger.with_context(log_context) do
    matches.each do |player_a, player_b|
      # TODO: battle can take a while, can be parallelized
      winner, loser = battle(player_a, player_b)
      update_players_elo(winner, loser)
    end
  end
  build_report
end