update doc

Author: Mohammad Hunan Chughtai

source/sdk/node/data-types/collections.txt

@@ -13,4 +13,32 @@ Collections - Node.js SDK
    :class: singlecol
 
 Overview
---------
+--------
+
+{+service-short+} has several types to represent groups of objects,
+which we call **collections**. A collection is an object that contains
+zero or more instances of one :ref:`{+service-short+} type
+<node-object-types>`. {+service-short+} collections are **homogenous**:
+all objects in a collection are of the same type.
+
+You can filter and sort any collection using {+client-database+}'s
+:ref:`query engine <node-client-query-engine>`. Collections are
+:ref:`live <node-live-object>`, so they always reflect the current state
+of the :term:`{+realm+} instance` on the current thread. You can also
+listen for changes in the collection by subscribing to :ref:`collection
+notifications <node-register-a-collection-change-listener>`.
+
+Lists
+-----
+
+
+Overview
+Lists & LinkingObjects
+Results Collection
+Results are Lazily Evaluated
+Collections are Live
+Working With Collections
+   Iteration
+   Limiting Query Results
+   Pagination
+Summary