added docs

doc/Paginator.md

@@ -0,0 +1,16 @@
+Pagination Adapter
+==================
+
+#### Example:
+
+```php
+// note: the cursor is not executed until you receive items from the pagination adapter
+$cursor            = $documentManager->getRepository('Users')->findAll();
+$paginationAdapter = DoctrineMongoODMModule\Paginator\Adapter\DoctrinePaginator($cursor);
+
+// Get first 5 users. Only the first five users are fetched from MongoDB.
+$users = $paginationAdapter->getItems(0, 5);
+
+// If you call it the second time, a new query is executed on MongoDB.
+$users2 = $paginationAdapter->getItems(5, 5);
+```