README更新.

使い方がちょこっと変わったのでREADMEも更新.
Roulette change Class.
Update README.md
Merge branch 'RouletteClass' of github.com:yuji-shimoda/LabRoulette into yuji-shimoda-RouletteClass

微調整.
1番点数の低い人もKyokoさんにsayしてもらう.

Conflicts:
	README.md