Support for MySQL and PostgreSQL should also be added for users or hosting environments that prefer MySQL/PGSQL. As database abstraction layer SQLAlchemy seems to be the best solution for Python (supports Python2/3, available in Debian, extensive documentation).

This also (hopefully) eases the task of changing the database schema to support new features such as #27 (which is currently non-functional).

If possible, SQLAlchemy can use its own connection pool or set up on the existing locking mechanism for threads/processes/uWSGI.