title: Can't update multiple records on tables with hasMany in CakePhp
body: <p>I have a table "Topic" that is linked to "Post" with hasMany in the model.</p>
  
  <p>I can't figure out how to update the two tables at once. </p>
  
  <p>This is my $this->request->data</p>
  
  <pre><code>Array
  (
    [Topic] =&gt; Array
        (
            [id] =&gt; 1
            [topic_title] =&gt; This is my topic
        )
  
    [Post] =&gt; Array
        (
            [1] =&gt; Array
                (
                    [id] =&gt; 1
                    [title] =&gt; Blah
                    [message] =&gt; My message
                )
  
            [2] =&gt; Array
                (
                    [id] =&gt; 2
                    [title] =&gt; Second Blah
                    [message] =&gt; Second My message
                )
  
        )
  
  )
  </code></pre>
  
  <p>I've tried to do like this :</p>
  
  <pre><code>$this-&gt;Topic-&gt;save($this-&gt;request-&gt;data);
  
  $this-&gt;loadmodel('Post');
  
  $this-&gt;Post-&gt;updateAll($this-&gt;request-&gt;data, array('Post.topic_id' =&gt; $id));
  </code></pre>
  
  <p>This is clearly the wrong approach however I struggling to find a good way of doing this.</p>