title: Updating a collection on Mongo
body: <p>Let´s say I have the following</p>
  
  <blockquote>
    <p>db.companies.insertOne({name: "Fresh Apples Inc", isStartup: true, employees: 33, funding: 12345678901234567890, details:{ceo: "Mark"}, tags: [{title: "super"}, {title: "perfect"}], foundingDate: new Date(), insertedAt: new Timestamp()})</p>
  </blockquote>
  
  <p>Now I need to update this and include a new detail so I would have details: <code>{ceo: "Mark", city: "New York"}</code></p>
  
  <pre><code>{
          "_id" : ObjectId("5c71b362b3458dab6ca76419"),
          "name" : "Fresh Apples Inc",
          "isStartup" : true,
          "employees" : 33,
          "funding" : 12345678901234567000,
          **"details" : {
              "ceo" : "Mark",
              "address" : "New York"
          },**
          "tags" : [
                  {
                          "title" : "super"
                  },
                  {
                          "title" : "perfect"
                  }
          ],
          "foundingDate" : ISODate("2019-02-23T20:56:02.380Z"),
          "insertedAt" : Timestamp(1550955362, 1)
  }
  </code></pre>
  
  <p>How can I update this without losing <strong>"ceo" : "Mark"</strong>?</p>