title: Node/Mongoose .populate() model after a POST and returning 201 created
body: <p>Using a typical example of POST'ing a <code>Post</code>, everything seems to be working as expected, and it's saving the <code>User</code> ObjectId in the Database etc.</p>
  
  <p>When it <strong>returns the results, I can't seem to get it to populate the User though</strong></p>
  
  <pre><code>Posts.createAsync(req.body)
      .then(saveUpdates(req.body))
      .then(responseWithResult(res, 201));
  
  
  function saveUpdates(updates) {
      return function (entity) {
          var updated = _.merge(entity, updates);
          return updated.saveAsync()
          .spread(function (updated) {
              return updated;
          });
      };
  }
  </code></pre>
  
  <p>Here's where I need it to just re-populate and return the full <code>Post</code> model with the populated <code>User</code></p>
  
  <pre><code>function responseWithResult(res, statusCode) {
      statusCode = statusCode || 200;
  
      return function (entity) {
          if (entity) {
              // Here's where I've tried just about everything I can think of
  
              // entity.populate('user') (doesn't work)
  
              res.status(statusCode).json(entity);
          }
      };
  }
  </code></pre>
  
  <hr>
  
  <blockquote>
    <p>Note: In a GET everything works and it populates the <code>User</code>, but for some reason the typical <code>.populate().execAsync()</code> doesn't seem to work here...</p>
  </blockquote>
  
  <pre><code>Posts.find({ "team" : req.params.id})
      .populate({ path: 'user' })
      .execAsync(function (err, posts) {
          res.json(posts);
  });
  </code></pre>
  
  <p>What am I missing in the POST return?</p>
  
  <hr>
  
  <p>The models aren't anything fancy, basically just:</p>
  
  <pre><code>var PostsSchema = new Schema({
      user : {
          type: Schema.ObjectId, 
          ref: 'User'
      },
      message : String
  });
  
  var UserSchema = new Schema({
      name: String,
      // etc etc
  });
  </code></pre>