By default all web2py applications are created with a db.py file where the database abstraction layer (DAL) is configured. When you create a model in the DAL, a database schema is generated in the target database, as well as an interface for that schema with no additional coding. You can use any number of databases, but the default is Sqlite which ships with web2py.
Part of the scaffolding found in db.py includes the code below which creates 6 auth tables, auth_user, auth_group, auth_membership, auth_permission, auth_event, and auth_cas.
An interface for each of these tables is automatically generated when you click on the database administration button.
