title: How to insert data with cakephp 3
body: <p>I want insert data with cakephp3 but it dont ok. The insert of data is ok at 50%. I dont have error which is return.</p>
  
  <pre><code>        class SeancesTable extends Table
  {
      public function initialize(array $config)
      {
          //$this-&gt;hasMany('Exercices');
          $this-&gt;hasMany('Series');
          $this-&gt;belongsToMany('Exercices');
          $this-&gt;addBehavior('TimesTamp');
      }
  }
  
  class SeriesTable extends Table
  {
      public function initialize(array $config)
      {
          parent::initialize($config);
  
          $this-&gt;table('series');
          $this-&gt;displayField('id');
          $this-&gt;primaryKey('id');
  
          $this-&gt;belongsTo('Seances');
          //$this-&gt;hasOne('Seances');
  
      }
  
      public function add(){
  
          $requestData = [
              'Seances' =&gt;[
                  'commentaire' =&gt; 'test cake 33',
                  'date_seance' =&gt; '2016-02-27',
                  'user_id' =&gt; 1,
                  'Series' =&gt; [
                      ['nb_rep' =&gt; 17, 'charge' =&gt; 520, 'exercice_id'=&gt;1],
                      ['nb_rep' =&gt; 27, 'charge' =&gt; 600]
                  ]
              ]
          ];
  
          $seance = $this-&gt;Seances-&gt;newEntity($requestData,[
              'associated' =&gt; ['Series']
          ]);
         $this-&gt;Seances-&gt;save($seance);
      }
  </code></pre>
  
  <p>In my database the data Seances are insert but not the series data.
  How can i do ?</p>
  
  <p>Thanks and sorry for my english !!</p>