[feat] added documentation

[yuxiaolejs]

No description provided.

[yuxiaolejs]

Why you changed it????? It's already up to date in master! This led to a merge conflict.....

PLEASE ASK PEOPLE WHO OWN THE BRANCH BEFORE COMMITING TO THEIR BRANCH
@luxiangzh

[luxiangzh]

Why you changed it????? It's already up to date in master! This led to a merge conflict.....

PLEASE ASK PEOPLE WHO OWN THE BRANCH BEFORE COMMITING TO THEIR BRANCH @luxiangzh

1. I updated it at 01:00:23 on g-action branch, with commit hash c3d8e5e。
2. You updated it at 01:18:04 on w2-fix-b01 branch, with commit hash 85d262d.
3. It was not up-to-date by the time I edited it. It became "up-to-date" by the time you made that comment because you merged pull request from w2-fix-b01 first, though it was opened later.
4. I viewed g-action branch as a branch designed to update github action, therefore I did the update here. I didn't consider it as a branch for triggering github action since the action triggers were set for the master branch at that time.
5. You don't need to capitalize all words to yell at me. Thank you.

[yuxiaolejs]

This branch will NOT get merged to keep junk files outside of master