Merged the "accounting.database" module into the "accounting" module. It has only one member as "db", the database instance, and does not need to be separated into another file.

src/accounting/models.py

@@ -25,7 +25,7 @@ from flask import current_app
 from flask_babel import get_locale
 from sqlalchemy import text
 
-from accounting.database import db
+from accounting import db
 from accounting.utils.user import user_cls, user_pk_column