If you need to clear out the entire database and start from scratch -- for
example, when pulling a commit that modifies the database schema -- the easiest
thing to do is delete the database and reinitialize an empty database.
An example session for this is below; make sure before executing these
commands that you have activated the virtual environment
(source .venv/bin/activate) for the backscope project.
dropdb <database_name>
createdb <database_name>
rm -rf migrations
flask db init
flask db migrate
flask db upgrade