title: How join/combine results from mongoDB
body: <p>I'm dev a card game. I have a catalog of cards in my game, let's say table "Catalog":</p>
  
  <pre><code>[
    {
      "id": 1,
      "name": "my spell",
      "type": "spell",
      "cost": 120
    }
  ]
  </code></pre>
  
  <p>On another table (name playerCards) I have all the cards that a player has. On that structure I don't want to repeat all information I have set-up for the card on the catalog. I only need to store the id of the card and the amounts:</p>
  
  <pre><code>[
    {
      "id": 1,
      "card_count_in_book": 10,
      "card_count_in_deck": 1
    }
  ]
  </code></pre>
  
  <p>And I'd like to know how can I make a query to return all card from a player in the following format:</p>
  
  <pre><code>[
    {
      "id": 1,
      "card_count_in_book": 10,
      "card_count_in_deck": 1,
      "name": "my spell",
      "type": "spell",
      "cost": 120
    }
  ]
  </code></pre>