title: How to query Start and End Elements in Order from an Array?
body: <p>I have a query but I don't know how to write
  I have tour collection with embedded points.</p>
  
  <pre><code>{
      _id: "my tour",
      points: [
          {_id: '1', point: 'A'},
          {_id: '2', point: 'B'},
          {_id: '3', point: 'C'},
          {_id: '4', point: 'D'}
      ]
  }
  </code></pre>
  
  <p>When user search tour start at B &amp; end at C  I want to list this document</p>
  
  <p>But when user search: start at C &amp; end at B the tour will not be listed.</p>
  
  <p>How I can write the this query?</p>