To set up the development environment:

1. `docker-compose up -d postgres`
2. `docker-compose up -d airflow37`  # or other version
3. `docker logs -f airflow_airflow37_1`
4. Wait until you see "Installation ready. Start doing nothing..."
5. `docker exec -it airflow_airflow37_1 bash`
6. You're good to go, e.g.:

    - `airflow webserver`
    - `airflow scheduler`
    - `nosetests tests/testfile.py:Class.testname -s`

***Note: Postgres image only supports one database at a time (without hacking), thus one development environment at a time. So bring only a single Airflow instance up with this script.***