Add reading api

- updateReadingByReadingId
- finishReadingByReadingId
- abandonedReadingByReadingId

PS. not finished
Fix reading api

- Add parameter 'reading[private]'
- Modify test case
Fix `PUT` method API

- Use `x-www-form-urlencoded` instead of `form-data` in payload
Build
Merge pull request #4 from eCrowdMedia/feature/extent-reading-api

Feature/extent reading api