Merge pull request #569 from gnuboard/fix/PY-44_table_prefix

fix: 그누보드6 설치 DB_TABLE_PREFIX 미적용 오류 수정

Author: KimTom89

core/database.py

@@ -3,7 +3,6 @@
 from fastapi import Depends
 from sqlalchemy import create_engine
 from sqlalchemy.engine import Engine, URL
-from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.ext.declarative import declared_attr
 from sqlalchemy.orm import Session, sessionmaker
 from sqlalchemy.pool import QueuePool