fix: use relative imports for python files

backend/db/database.py

@@ -2,7 +2,7 @@ from databases import Database
 from sqlalchemy import create_engine, MetaData
 from sqlalchemy.orm import declarative_base
 
-from backend.config import settings
+from ..config import settings
 
 # for Alembic migrations and sync operations
 engine = create_engine(settings.database_url)