브랜치가 가르키는 버전을 바꾼다
- remove 1 commit
- make 3 commit to 1
if argument is branch then refer reference of that branch (안연결될 놈들은 접근 못하기 때문에 삭제, 취소처럼 느껴지는거)
—hard make all delete, —soft just move
- revert all

Seonglae Cho
Seonglae Cho—hard make all delete, —soft just move