title: Add ranking system in returned query document?
body: <p>My User collection contains the following documents:</p>
  
  <pre><code>{"_id" : 1, point_count: "12"},
  {"_id" : 2, point_count: "19"},
  {"_id" : 3, point_count: "13"},
  {"_id" : 4, point_count: "1233"},
  {"_id" : 5, point_count: "1"},
  ... and about 1000 more
  </code></pre>
  
  <p>My question is: Is it possible to show ranking of each user based on point_count field when I search by id? let say I use this query to find user with id = 4</p>
  
  <pre><code>db.User.find({_id: 4})
  </code></pre>
  
  <p>let assume highest point_count in my entire collection is 1233, I'm hoping to get this result </p>
  
  <pre><code>{"_id" : 4, point_count: "1233", rank: 1}
  </code></pre>
  
  <p>rank 1 because 1233 is the highest point_count</p>
  
  <p>or when I search user with id = 5, my expect result should be</p>
  
  <pre><code>{"_id" : 5, point_count: "1", rank: 1000..something}
  </code></pre>
  
  <p>1000..something because it is the lowest rank and there are around 1000+ id in the document.
  Thank you all so much for helping me here!</p>