Merge pull request #12 from MaxMEllon/fix

Fix
fix: コンストラクタの書き方修正
fix: boardの初期化の方法を変更
fix: ちゃんと裏返るように処理
Merge pull request #14 from MaxMEllon/fix

merge: fix -> develop
Merge pull request #15 from MaxMEllon/develop

merge: develop -> master