Fixed #69
Add created, updated dates. fixed #70
Refactor. fixed #67
Fixed #66
Merge pull request #71 from KazumaKobayashi/feature

Session対応、バグ修正
Remove lines. fixed #76
Fixed empty response bug. fixed #74
Small refactor.
Merge pull request #72 from KazumaKobayashi/develop

Session対応とか、Refactoringとか