title: Does Laravel Schema manages polymorphic associations out of the box?
body: <p>I'd like to create some <em>commentable</em> models for a project, but I cannot find any references to create the comments migration script, I've only found this video on vimeo: <a href="http://vimeo.com/53183075" rel="noreferrer">Laravel 4 - Eloquent Collections &amp; Polymorphic Relations</a>.</p>
  
  <p>Am I supposed to add the polymorphic columns explicitly?</p>
  
  <pre><code>Schema::create('comments',function($table){
      $table-&gt;increments('id');
      $table-&gt;text('body');
      $table-&gt;string('commentable_type');
      $table-&gt;integer('commentable_id');
      $table-&gt;timestamps();
  });
  </code></pre>
  
  <p>Question comes as the builder do expects the programmer when a key is a foreign key as in <code>$table-&gt;foreign('user_id')-&gt;references('id')-&gt;on('users');</code></p>