title: Can I use something like findAndModify on a deep nested document with MongoDB?
body: <p>I have the Collection <strong>contexts</strong> with documents like the following in my MongoDB (a <strong>context</strong> has some <strong>users</strong> with <strong>roles</strong>)</p>
  
  <pre><code>{
      "__v" : 0,
      "_id" : ObjectId("53dea71a713d636e1fea705a"),
      "name" : "team4",
      "users" : [ 
          {
              "userId" : "53a347467f311d7c1731f91b",
              "roles" : [ 
                  "admin"
              ]
          }, 
          {
              "userId" : "536d2e8be0f9697e13b95c87",
              "roles" : []
          }
      ]
  }
  </code></pre>
  
  <p>Is there a way to add (or remove) a <strong>role</strong> to a <strong>user</strong> with <a href="http://docs.mongodb.org/manual/reference/command/findAndModify/" rel="nofollow">findAndModify</a>. </p>