fix part 3

backend/app/database/models/board.py

@@ -1,10 +1,10 @@
 """Board database model."""
 
-from datetime import datetime, timezone
+from datetime import datetime
 from typing import TYPE_CHECKING
 from uuid import UUID, uuid4
 
-from sqlalchemy import Boolean, DateTime, ForeignKey, String, Text
+from sqlalchemy import Boolean, DateTime, ForeignKey, String, Text, func
 from sqlalchemy.dialects.postgresql import JSONB
 from sqlalchemy.dialects.postgresql import UUID as PGUUID
 from sqlalchemy.orm import Mapped, mapped_column, relationship
@@ -42,9 +42,9 @@ class Board(Base):
         default=lambda: {"x": 0, "y": 0, "zoom": 1.0, "rotation": 0},
     )
 
-    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc))
+    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, server_default=func.now())
     updated_at: Mapped[datetime] = mapped_column(
-        DateTime, nullable=False, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc)
+        DateTime, nullable=False, server_default=func.now(), onupdate=func.now()
     )
     is_deleted: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)