create boolean value that could be nilled
class AddActiveToQuestionnaire < ActiveRecord::Migration[7.2]
def change
add_column :questionnaires, :active, :boolean
add_check_constraint :questionnaires, "active", name: "only_accept_true_or_null"
add_index :questionnaires, :active, unique: true
end
end
https://github.com/buncis/norma/commit/2ee90bb3e57fde446a24e59b1087714f2239f845