Task.php

<?php
class Task extends Doctrine_Record {
   public function setUp() {
      $this->hasMany('Resource as ResourceAlias', 'Assignment.resource_id');
      $this->hasMany('Task as Subtask', 'Subtask.parent_id');
   } 
   public function setTableDefinition() {
      $this->hasColumn('name', 'string',100); 
      $this->hasColumn('parent_id', 'integer'); 
   }
}