gistfile1.php

<?php

// config/ProjectConfiguration.class.php
class ProjectConfiguration extends sfProjectConfiguration
{
  // ...

  public function configureDoctrineConnection(Doctrine_Connection $conn)
  {
    $listener = new ConnectionListener(
      $this->getMasterConnection()->getDbh(),
      $this->getSlaveConnection()->getDbh()
    );

    $conn->addListener($listener);
  }
}