title: Why is the apostrophe-pages _children array is always empty?
body: <p>I am trying to get the children of apostrophe pages to appear in my navigation object - however the _children array is always empty. My page does have child pages set up via the front end Pages UI. </p>
  
  <p>My index.js for the lib/modules/apostrophe-pages module contains the following:</p>
  
  <pre><code>  construct: function(self,options) {
        // store the superclass method and call at the end
        var superPageBeforeSend = self.pageBeforeSend;
        self.pageBeforeSend = function(req, callback) {
  
      // Query all pages with top_menu setting = true and add to menu collection
      self.apos.pages.find(req, { top_menu: true }, {slug: 1, type: 1, _id: 1, title: 1})
         .children(true)
         .toArray(
             function (err, docs) {  
                if (err) {
                   return callback(err);
                }
                req.data.navpages = docs;
                return superPageBeforeSend(req, callback);
             });
      };
  
    },   
  ...
  </code></pre>
  
  <p>My top_menu attribute is set via apostrophe-custom-pages:</p>
  
  <pre><code>module.exports = {
    beforeConstruct: function(self, options) {
      options.addFields = [
        {
          name: 'subtitle',
          label: 'Subtitle',
          type: 'string'
        },
        {
          name: 'css_class',
          label: 'CSS Class',
          type: 'string'
        },
        {
          name: 'top_menu', 
          label: 'Include In Top Menu',
          type: 'boolean'
        }
      ].concat(options.addFields || []);
     }
  };
  
  </code></pre>
  
  <p>This gives me the pages I need with the top_menu setting.. but I want to get child pages too..</p>
  
  <p>When debugging the code I can see that the docs._children array is present but is always empty, even though a page has child pages...</p>
  
  <p>I have tried adding the following both to my app.js and to my index.js but it doesn't change the result: </p>
  
  <pre><code>  filters: {
      // Grab our ancestor pages, with two levels of subpages
      ancestors: {
        children: {
          depth: 2
        }
      },
      // We usually want children of the current page, too
      children: true
    }
  </code></pre>
  
  <p>How can I get my find() query to actually include the child pages?</p>