fix part 2

backend/app/database/models/user.py

@@ -1,7 +1,7 @@
 """User model for authentication and ownership."""
 
 import uuid
-from datetime import datetime
+from datetime import datetime, timezone
 
 from sqlalchemy import Boolean, Column, DateTime, String
 from sqlalchemy.dialects.postgresql import UUID
@@ -18,8 +18,8 @@ class User(Base):
     id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
     email = Column(String(255), unique=True, nullable=False, index=True)
     password_hash = Column(String(255), nullable=False)
-    created_at = Column(DateTime, nullable=False, default=datetime.utcnow)
-    updated_at = Column(DateTime, nullable=False, default=datetime.utcnow, onupdate=datetime.utcnow)
+    created_at = Column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc))
+    updated_at = Column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc))
     is_active = Column(Boolean, nullable=False, default=True)
 
     # Relationships