title: Get model class from symbol
body: <p>I'm implementing a method, that will be used in many places of a project.</p>
  
  <pre><code>def do association
  
  end
  </code></pre>
  
  <p>"association" is a symbol, like <code>:articles</code>, <code>:tags</code>, <code>:users</code> etc.</p>
  
  <p>When the association is <code>:articles</code>, I need to work with the Article model.</p>
  
  <p>When the association is <code>:users</code>, I need to work with the User model.</p>
  
  <p>Etc.</p>
  
  <p>I know, that I can write a helper method, that returns model class, depending on the provided symbol. But is there a ready to use method for that?</p>