title: Private methods in Ruby
body: <p>An example of Rails controller which defines a private method:</p>
  
  <pre><code>class ApplicationController &lt; ActionController::Base
    private
    def authorization_method
      # do something
    end
  end
  </code></pre>
  
  <p>Then, it's being used in a subclass of <code>ApplicationController</code>:</p>
  
  <pre><code>class CustomerController &lt; ApplicatioController
    before_action :authorization_method
  
    # controller actions
  end
  </code></pre>
  
  <p>How is it possible that a private method is called from its subclass? What is the meaning of <code>private</code> in Ruby?</p>