title: find not working on mongoose document
body: <p>My model looks like this</p>
  
  <pre><code>/* models/songs.js */
  var mongoose = require('mongoose');
  
  var SongsSchema = new mongoose.Schema({
      genres: [ String ],
      popularity: Number,
      trackId: String,
      artistIds: [ String ],
      users: [ String ],
      trackName: String // human readability
  });
  
  var Songs = mongoose.model("Songs", SongsSchema);
  
  module.exports = {
    Songs: Songs
  };
  </code></pre>
  
  <p>This is what is in my routes</p>
  
  <pre><code>/* routes/index.js */
  var mongoose = require('mongoose');
  var Songs = mongoose.model('Songs');
  
  router.get('/api/genre', function(req, res, next) {
    var genre = req.query.genre.replace(/%26/, '&amp;');
    genre = req.query.genre.replace(/-/g, ' ');
  
    console.log('attempting to find', genre);
    Songs.find({
      genres: genre
    }, function(err, songs, count) {
      console.log('count', count);
      console.log('songs', songs);
  
      res.json(songs.map(function(song) {
        console.log('hello ', song);
        return song.trackId;
      }));
    });
  });
  </code></pre>
  
  <p>"attemping to find" logs out perfectly fine, but none of the lines in the Songs.find callback is logging out anything. The weird part about this is that it's not giving me any error. Another weird thing is that I also tried used the Songs.find in other parts of <code>routes/index.js</code> and they work fine. I've also tried using <code>findOne</code> and other functions on my Songs document, but they don't seem to be working. I've also tried looking at other StackOverflow questions, but none of them seem to have my answer.</p>