fix part 3

backend/app/database/models/user.py

@@ -1,9 +1,8 @@
 """User model for authentication and ownership."""
 
 import uuid
-from datetime import datetime, timezone
 
-from sqlalchemy import Boolean, Column, DateTime, String
+from sqlalchemy import Boolean, Column, DateTime, String, func
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
 
@@ -18,8 +17,8 @@ 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=lambda: datetime.now(timezone.utc))
-    updated_at = Column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc))
+    created_at = Column(DateTime, nullable=False, server_default=func.now())
+    updated_at = Column(DateTime, nullable=False, server_default=func.now(), onupdate=func.now())
     is_active = Column(Boolean, nullable=False, default=True)
 
     # Relationships