title: How to combine queries in docpad?
body: <p>I need to get only last week posts. I don't find examples in <a href="https://learn.bevry.me/queryengine/guide" rel="nofollow">Documentation</a> and for tests I use <a href="http://bevry.github.io/query-engine/demo/code.html" rel="nofollow">Query-Engine demo</a> with this code:</p>
  
  <pre><code>models = [
          title: 'WRONG: Future'
          date: new Date("2015-05-23")
      ,
          title: 'Correct 1'
          date: new Date("2015-05-22")
      ,
          title: 'Correct 2'
          date: new Date("2015-05-20")
      ,
          title: 'WRONG: Old'
          date: new Date("2015-05-15")
  ]
  
  max_date = min_date = new Date("2015-05-22");
  min_date.setDate(min_date.getDate() - 7);
  
  result = queryEngine.createCollection(models)
      .findAll({
          $and: {
              date: {
                  $lte: max_date
              },
              date: {
                  $gt: min_date
              }
          }
      }).toJSON()
  
  return result
  </code></pre>
  
  <p>How to get posts in this slice?</p>