title: Ruby: Is it possible to define a class method in a module?
body: <p>Say there are three classes: <code>A</code>, <code>B</code> &amp; <code>C</code>. I want each class to have a class method, say <code>self.foo</code>, that has exactly the same code for <code>A</code>, <code>B</code> &amp; <code>C</code>.</p>
  
  <p>Is it possible to define <code>self.foo</code> in a module and include this module in <code>A</code>, <code>B</code> &amp; <code>C</code>? I tried to do so and got an error message saying that <code>foo</code> is not recognized.</p>