Updating LB

Change 01/01/2020: Since this date, the migration folder have changed (due to all errors, it was easier to remake it from scratch).
If you already used the application and need to upgrade, please edit your `alembic_version" table, and set the "version_num" column to "1". This will allow you to use the new migration scripts.

To update the application, simply update the files then run the following:

# get into the virtualenv
source env/bin/activate

# update the DB
python manage.py db upgrade
# update the static files
npm run dist
# update the SDE
python manage.py sde_import -d