이미 커밋된 파일을 ignore 하기

1.  i.e., stop tracking the file but not delete it from your system use:

   git rm --cached filename

2. First commit any outstanding code changes, and then, run this command:

   git rm -r --cached .

3. To untrack every file that is now in your .gitignore

Ref

• Ignore files that have already been committed to a Git repository