* Bump version to v0.2.0
* Add changelog
* minor refine
* minor refine
* update date
* clean the code
* minor refine
* update release date
* Fix grammar
* Fix grammar
* Fix grammar
* Fix grammar
* Minor refine
* Fix error format in readme
* update date
* minor refine
* minor refine
* minor refine
* minor refine
* refine grammar