* refaictor CONTRIBUDING.MD

* refaictor CONTRIBUDING.MD

* fix source rvm shell command

* fix lint

* add chinese contributing.md

* fix error render

* fix error render

* refine description

* refine description

* minor refine

* install ffmpeg before ut

* Minor retfine

* Minor refine

* refine chinese contributing.md

* Refine

* Fix as comment

* Fix as comment

* restore pr.md

* minor refine

* minor refine

* update chinese CONTRIBUTING.md in root dir

* adjust imgae size

* update en CONTRIBUTING.md

* update en CONTRIBUTING.md

* update contributing.md in docs

* restore change of index.rst

* Fix as comment

* minor refine

* remove content in PR.md

* minor refine

* minor refine

* minor refine

* Fix as comment

* rename

* minor refine