Array#shuffleで同じ結果を得る
shuffleの引数に同じRandomオブジェクトを渡せば何度シャッフルしても同じ結果になる
$ pry [1] pry(main)> Array(1...10).shuffle(random: Random.new(473)) => [6, 4, 9, 5, 8, 3, 2, 1, 7] [2] pry(main)> Array(1...10).shuffle(random: Random.new(473)) => [6, 4, 9, 5, 8, 3, 2, 1, 7] [3] pry(main)> Array(1...10).shuffle(random: Random.new(473)) => [6, 4, 9, 5, 8, 3, 2, 1, 7]