title: insert ignore on duplicate entries in Doctrine2/Symfony2
body: <p>How to ignore on duplicate entries using Doctrine2?</p>
  
  <p>Error example:</p>
  
  <pre><code>SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'symfony' for key 'UNIQ_389B783389B783'
  </code></pre>