title: MongooseJS FindById ObjectId
body: <p>I have this simple schema:</p>
  
  <pre><code>var CategorySchema = new mongoose.Schema({
      name: String,
      description: String
  });
  </code></pre>
  
  <p>I get id as URL parameter:</p>
  
  <pre><code>var id = req.params.id;
  Category.findById(id, function(err, blogshop){
  ...
  });
  </code></pre>
  
  <p>Do I need to use <code>mongoose.Schema.Types.ObjectId;</code> or passing the <code>hex</code> value is ok? Thanks</p>