Add deleted_at field to Role model for soft-delete

app/models/role.py

@@ -7,6 +7,7 @@ from datetime import datetime
 from typing import Any
 
 from sqlalchemy import DateTime, Integer, String, func
+from sqlalchemy import Boolean
 from sqlalchemy.dialects.postgresql import JSONB
 from sqlalchemy.dialects.postgresql import UUID as PGUUID
 from sqlalchemy.orm import Mapped, mapped_column
@@ -34,3 +35,6 @@ class Role(Base, TenantMixin):
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), nullable=False, server_default=func.now()
     )
+    deleted_at: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True, default=None
+    )