add methods directly called on model
<p>I would like to implement my own method called on class load.</p>

<p>The first example I have is from <code>PaperClip</code> where the line <code>has_attached_file</code> is written directly on the class and refers to another implantation somewhere around (lib/Paperclip).</p>

<p>I would like to implement a method to be called for some other method on a class. I want it to looks link a <code>before_filter</code> but on a model. </p>

<p>This idea is to not have to call a specific method manually on each method you want to. Just one line at the beginning of the model should be enough to do it.</p>

<p>I tried using <code>Concern</code> but as far as I know, I can only define class/instance methods, include some dependencies and so on.</p>

<p>I would like to call the method <code>watch_here</code> for 2 methods <code>go_for_it</code> and <code>do_it_again</code>. I don't want to call it like that:</p>

<pre><code>def go_for_it
  watch_here :go_for_it
  puts "Do it!"
end

def do_it_again
  watch_here :do_it_again
  puts "Do it again!"
end

private
def watch_here(name)
  puts "I'm watching on #{name}"
end
</code></pre>

<p>I would rather have something like:</p>

<pre><code>watch_here :go_for_it, :do_it_again
</code></pre>

<p>Thank you for you help!</p>