title: Promise has no method 'sort'
body: <p>I am using Mongoose with Bluebird and am hitting an Error when using a query that includes a sort on a time stamp.  I am trying to retrieve only the most recent entry.  The query works when using the built in Promises.</p>
  
  <p>Any ideas?  Thanks!</p>
  
  <pre><code>var Promise        = require("bluebird"),    
      mongoose       = require('mongoose');
  
  var Item = Promise.promisifyAll(mongoose.model("Item"));
  Promise.promisifyAll(Item.prototype);
  var connect = function () {
      var options = { server: { socketOptions: { keepAlive: 1 } } };
      var mongoUrl = "mongodb://" + config.mongo.host + ":" + config.mongo.port + "/" + config.mongo.db;
    mongoose.connect(mongoUrl, options);
  }; 
  connect();
  
  Item.findAsync({item_id: "03010200400000a0bf00210"}).sort({ts:-1}).limit(1);
  </code></pre>
  
  
  
  <pre><code>Possibly unhandled TypeError: Object [object Promise] has no method 'sort'
      at Object.module.exports.process (/Source/updater2/checkAndUpdate.js:88:75)
      at /Source/tellme/updater2/test1.js:25:20
      at tryCatch1 (/Source/updater2/node_modules/bluebird/js/main/util.js:43:21)
      at Promise$_callHandler [as _callHandler] (/Source/updater2/node_modules/bluebird/js/main/promise.js:627:13)
      at Promise$_settlePromiseFromHandler [as _settlePromiseFromHandler] (/Source/updater2/node_modules/bluebird/js/main/promise.js:641:18)
      at Promise$_settlePromiseAt [as _settlePromiseAt] (/Source/updater2/node_modules/bluebird/js/main/promise.js:804:14)
      at Promise$_settlePromises [as _settlePromises] (/Source/updater2/node_modules/bluebird/js/main/promise.js:938:14)
      at Async$_consumeFunctionBuffer [as _consumeFunctionBuffer] (/Source/updater2/node_modules/bluebird/js/main/async.js:75:12)
      at Async$consumeFunctionBuffer (/Source/updater2/node_modules/bluebird/js/main/async.js:38:14)
      at process._tickCallback (node.js:419:13)
  Mongoose:item.find({ item_id: '03010200400000a0bf00210' }) { fields: undefined }  
  </code></pre>