Forbid model from get saved or destroyed in Ruby on Rails

readonly_model.rb

module Util::ReadonlyModel
  extend ActiveSupport::Concern

  included do
    before_destroy :raise_readonly
  end

  def readonly?
    true
  end

  def raise_readonly
    raise ActiveRecord::ReadOnlyRecord
  end
end

#Usage
class YourReadonlyModel < ActiveRecord::Base
  include Util::ReadonlyModel
end