User seems to need a new attribute

[alexanderisora]

Hello. Thank a lot for such a precious gem!
Do I need to perform some migration to start adding roles?

rails -v
>Rails 5.0.4

2.3.3 :001 > User.first.roles
WARNING: `roles' is not an attribute of `Class'. But, it's ok if it happens during migrations and your "bitmasked" attribute is still not created.

2.3.3 :003 > User.first.roles << :admin
  User Load (1.5ms)  SELECT  "users".* FROM "users" ORDER BY "users"."id" ASC LIMIT ?  [["LIMIT", 1]]
ActiveModel::MissingAttributeError: can't write unknown attribute `roles`