acts_as_public.rb

module ActsAsPublic
  
  extend ActiveSupport::Concern

  # This modules assumes you have a column 
  # called 'public' that is by default true

  included do
    default_scope where(public: true)
  end

  module ClassMethods
    def not_public
      where(public: false)
    end
  end

  # Instance methods
  def make_public!
    self.public = true
    save
  end

  def make_hidden!
    self.public = false
    save
  end

end