title: Doctrine ManyToMany relation with join condition
body: <p>I've got a Many-To-Many relation between two tables but I want to add a join condition on the join table.</p>
  
  <pre><code>/**
   * @ManyToMany(targetEntity="Company", inversedBy="Accounts")
   * @JoinTable(name="account_company",
   *      joinColumns = { @JoinColumn(name="account_id", referencedColumnName="id") },
   *      inverseJoinColumns = { @JoinColumn(name="company_id", referencedColumnName="id") }
   * )
   */
  protected $companies;
  </code></pre>
  
  <p>I would have a condition like "account_company.is_deleted = 0", how can I make it ?</p>