rapid interations of server side app and firefox extension

backend/app/models/base.py

@@ -0,0 +1,17 @@
+"""SQLAlchemy base model."""
+
+from datetime import datetime
+from sqlalchemy import func
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
+
+
+class Base(DeclarativeBase):
+    """Base class for all models."""
+    pass
+
+
+class TimestampMixin:
+    """Mixin for created_at and updated_at timestamps."""
+
+    created_at: Mapped[datetime] = mapped_column(default=func.now())
+    updated_at: Mapped[datetime] = mapped_column(default=func.now(), onupdate=func.now())