Adding LDAP login

app/models/role.py

@@ -1,4 +1,4 @@
-from sqlalchemy import String
+from sqlalchemy import Boolean, String
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from app.core.database import Base
@@ -11,6 +11,9 @@ class Role(Base):
     id: Mapped[int] = mapped_column(primary_key=True)
     name: Mapped[str] = mapped_column(String(64), unique=True, index=True)
     description: Mapped[str | None] = mapped_column(String(255), default=None)
+    # The role auto-assigned to newly provisioned/registered users. At most one
+    # role is the default; see ``crud.role.set_default``.
+    is_default: Mapped[bool] = mapped_column(Boolean, default=False)
 
     users: Mapped[list["User"]] = relationship(  # noqa: F821
         secondary=user_roles,