attr_accessor default values

I'm using rails and I want to make it so that attr_accessor :politics is set, by default, to false.

Does anyone know how to do this and is able to explain it in simple terms for me?

Rails 4+

class Like < ApplicationRecord
  def after_initialize
    self.politics = false
  end
end

i = Like.new
i.politics #=> false

Rails 3.1 and below

class Like
  attr_accessor_with_default :politics, false
end

i = Like.new
i.politics #=> false

Pure Ruby

class Like
  attr_writer :politics
      
  def politics
    @politics || false
  end
end

i = Like.new
i.politics #=> false