title: Where to put code when monkey patching
body: <p>Everything I read about monkey patching says to do something like this:</p>
  
  <pre><code>class String
    def foo
      #your special code 
    end
  end
  </code></pre>
  
  <p>But I can't find any instructions on where to put this code. In a rails app, can I just put this any crazy place I want? In a Module? A Model? </p>
  
  <p>Do I need to include something in the file where I define my monkeypatch? Do I need to include my monkeypatch everywhere where I want to use it?</p>