title: Add and update subdocument in mongoDB and node js (without mongoose)
body: <p>I'm fairly new to node js and mongoDB and I need to add or update a Subdocument on mongodb collection as follow :</p>
  
  <pre><code>{
      "_id": "58286e49769e3729e895d239",
      "id": "2",
      "title": "Session Title",
      "sessiondate": "2016-02-11T21:00:00.000Z",
      "startTime": "14:30",
      "endTime": "16:30",
      "breakStartTime": "16:30",
      "breakEndTime": "18:00",
      "talks": [
          {
              "id": "3",
              "title": "Android",
              "speaker": {
                  "id": "1",
                  "name": "john doe",
                  "about": "about the speaker",
                  "photo": "https://pbs.twimg.com/profile_images/566353055788978177/dUy_ueY2.jpeg"
              }
          }
      ]
  }
  </code></pre>
  
  <p>All the solutions I have found is using mongoose, where in this specific project we decided not to use mongoose, any thoughts?</p>