การแก้ปัญหา migration with multiple heads - MUMT-IT/mis2018 GitHub Wiki
https://blog.jerrycodes.com/multiple-heads-in-alembic-migrations/
$ flask db merge heads -m "merge D and F"
https://blog.jerrycodes.com/multiple-heads-in-alembic-migrations/
$ flask db merge heads -m "merge D and F"