title: changing the field name in a leftjoin
body: <p>I have a Repo with this query</p>
  
  <pre><code>@EntityRepository(Refund)
  export class RefundRepository extends Repository&lt;Refund&gt; {
  getRefundsByUserId(id: number): Promise&lt;Refund[]&gt; {
  return this.createQueryBuilder('refund')
  .select([
    'refund.id',
    'refund.userId',
    'refund.amount',
    'refund.createdAt',
    'refund.updatedAt',
  ])
  .leftJoinAndSelect('refund.fkFlightRefund', 'flight')
  .leftJoinAndSelect('refund.currency', 'refundCurrency')
  .leftJoinAndSelect('refund.status', 'refundStatus')
  .where({  userId : id })
  .getMany();
  
  }
  </code></pre>
  
  <p>My problem is with the refund.fkFlightRefund , I want to return a field name "flight" but i get "fkFlightRefund", </p>
  
  <p>I also tried using this left join : </p>
  
  <pre><code>    .leftJoinAndSelect('refund.fkFlightRefund', 'flights' , 'refund.fkFlightRefund.title = :title',
  { title: 'flight' },)
  </code></pre>
  
  <p>after googling the issue ,</p>
  
  <p>is what i'm trying to do possible ? </p>
  
  <p>any help will do !</p>