title: Mongoose - finding in subdocument by criteria
body: <p>I've just got stuck with this problem. I've got two Mongoose schemas:</p>
  
  <pre><code>let userSchema = new mongoose.Schema({
              username: { type:String, default:null },
              email: { type:String, required:true },
              role: { type: mongoose.Schema.Types.ObjectId, ref: 'Role', required: true }, 
          });
  
  let roleSchema = new mongoose.Schema({
          name: { type:String, default:"Player" },
          privileges:
              [
                  {
                      resource: String ,
                      actions: [ String ]
                  },
              ],
  
      });
  </code></pre>
  
  <p>Question si how to find users with specific criteria for exemple Get All Users with Role Name = "super Admin" I try this by no result</p>
  
  <pre><code>User.find({'role.name':'Super Admin'}).populate('role')
      .exec()
      .then(results =&gt; {
          res.success(results);
      }, error =&gt; {
          res.error(error);
      })
  </code></pre>