title: Laravel 5.1 eloquent::attach() method with timestamps
body: <p>I seem to have a problem with timestamps - when trying to attach <code>User</code> to <code>Lectures</code> via <code>favorites</code> pivot table - none of the dates updates.</p>
  
  <p>Here's my migration:</p>
  
  <pre><code>Schema::create('favorites', function (Blueprint $table) {
  
      $table-&gt;integer('lecture_id')-&gt;unsigned();
      $table-&gt;integer('user_id')-&gt;unsigned();
      $table-&gt;timestamps();
  
      $table-&gt;primary(['lecture_id', 'user_id']);
  
  });
  </code></pre>
  
  <p>Lecture relationship:</p>
  
  <pre><code>public function favorites()
  {
      return $this-&gt;belongsToMany(User::class, 'favorites');
  }
  </code></pre>
  
  <p>User relationship:</p>
  
  <pre><code>public function favorites()
  {
      return $this-&gt;belongsToMany(Lecture::class, 'favorites')
                  -&gt;withTimestamps();
  }
  </code></pre>
  
  <p>Whenever I attach:</p>
  
  <pre><code>$event-&gt;lecture-&gt;favorites()-&gt;attach($this-&gt;user-&gt;id);
  </code></pre>
  
  <p>Both fields <code>created_at</code> and <code>updated_at</code> are set to <code>0000-00-00 00:00:00</code></p>
  
  <p>Any idea what I might be doing wrong?</p>