title: knex js - one to many relation
body: <p>I am having two tables - Questions and Answers which are connected by foreign key on Answers named questionId. Each question may contain multiple answers. I am trying to create a single query to obtain questions with all fields and put answers into field of type array. For instance this is the question structure:</p>
  
  <pre><code>{
  id: 5
  name: "abc",
  answers: ["a","b","c"]
  }
  </code></pre>
  
  <p>How can I force knex to group by questionId and put all of them to answers?
  I tried to use leftjoins but it doesn't work for one to many relationships.
  This is what I've tried:</p>
  
  <pre><code> var questionQuery = this.knex.select().table(this.questionWithAnswersTb)
              .select("*")
              .leftJoin(this.answersTb, this.questionWithAnswersTb + ".id", this.answersTb + ".questionId");
  </code></pre>