What is a Ruby factory method?
<p>I understand that a factory method is a class method that utilises the <code>self</code> keyword and instantiates an object of it's own class. I don't understand how this is useful or how it can extend the functionality of <code>initialize</code> method.</p>

<p>I'm working on a project creating a command line address book that asks me to use a factory pattern on the Person class so that I can create a Trainee or Instructor (subclasses) with different attributes.</p>