Remember that Docker container's build context is the Github remote master branch. So you gotta push your changes and rebuild containers in order for them to work.
Set the following environment variables:
export SECRET_KEY=xxx
export DATABASE_URL=xxx
export DATABASE_TEST_URL=xxx
Run tests: python manage.py test
Create the database: python manage.py recreate_db
Seed the database with some users: python manage.py seed_db
After changing a model:
python manage.py db migrate
python manage.py db upgrade