title: Can I override the Mongoid push (i.e. <<) method for has_many or has_and_belongs_to_many relations?
body: <p>Lets say that I had a class</p>
  
  <pre><code>class Foo
    include Mongoid::Document
    include Mongoid::Timestamps
  
    has_many :bars
  end
  </code></pre>
  
  <p>Is there any way to override <code>some_foo.bars.push(some_bars)</code>?  Mostly I want to put in some business logic before calling the parent <code>#push</code>.</p>
  
  <p>Thanks!</p>