feat(rbac): add roles and permissions

backend/hermes/app/models/user.py

@@ -2,8 +2,10 @@ from datetime import datetime
 
 from sqlalchemy import Boolean
 from sqlalchemy import DateTime
+from sqlalchemy import ForeignKey
 from sqlalchemy import String
 from sqlalchemy import func
+from sqlalchemy.orm import relationship
 from sqlalchemy.orm import Mapped
 from sqlalchemy.orm import mapped_column
 
@@ -48,6 +50,13 @@ class User(Base):
         server_default="user"
     )
 
+    role_id: Mapped[int] = mapped_column(
+        ForeignKey("roles.id"),
+        index=True,
+    )
+
+    primary_role = relationship("Role", lazy="joined")
+
     is_active: Mapped[bool] = mapped_column(
         Boolean,
         default=True,