자기계발하는 쏭이

django 에서 models.py를 수정하고 migration을 하려고 하면 You are trying to add a non-nullable field '필드명' to post without a default; we can't do that (the database needs something to populate existing rows).Please select a fix: 1) Provide a one-off default now (will be set on all existing rows with a null value for this column) 2) Quit, and let me add a default in models.pySelect an option: 이런 메세지가 나올 때가 있다...