def password_archivable
      apply_devise_schema :encrypted_password, String, limit: 128, null: false
      apply_devise_schema :password_salt, String
      apply_devise_schema :password_archivable_id, Integer, null: false
      apply_devise_schema :password_archivable_type, String, null: false
      apply_devise_schema :created_at, DateTime
    end
def password_archivable
      apply_devise_schema :encrypted_password, String, limit: 128, null: false
      apply_devise_schema :password_salt, String
      apply_devise_schema :password_archivable_id, Integer, null: false
      apply_devise_schema :password_archivable_type, String, null: false
      apply_devise_schema :created_at, DateTime
    end
Add password_archivable columns

 Examples

 create_table :old_passwords do
   t.password_archivable
 end
 add_index :old_passwords, [:password_archivable_type, :password_archivable_id], name: 'index_password_archivable'