fixes and refactor

app/database/base.py

@@ -2,8 +2,7 @@
 Database configuration and session management
 """
 from sqlalchemy import create_engine
-from sqlalchemy.ext.declarative import declarative_base
-from sqlalchemy.orm import sessionmaker, Session
+from sqlalchemy.orm import declarative_base, sessionmaker, Session
 from typing import Generator
 
 from app.config import settings