# Do not allow edits unless explicitly directed by `#allow_next_update!` prior to saving
module Immutable
  extend ActiveSupport::Concern

  included do
    before_destroy :allow_next_update!
  end

  def allow_next_update!
    @allow_update = true
  end

  def readonly?
    if @allow_update
      @allow_update = false
      return false
    end

    return !new_record?
  end
end