Merge pull request #1 from jaypei/master

import路径修改
加入 TravisCI 支持
给 README 加入 CI 图标
Merge pull request #2 from jianingy/master

给 README 加入 CI 图标
Use oslo.db as db_backend
Merge pull request #3 from jianingy/master

Use oslo.db as db_backend