updating DIRECTORY.md

Author: github-actions

DIRECTORY.md

@@ -163,6 +163,9 @@
   * Hashset
     * [Test My Hashset](https://github.com/BrianLusina/PythonSnips/blob/master/datastructures/hashset/test_my_hashset.py)
   * Linked Lists
+    * Circular
+      * [Node](https://github.com/BrianLusina/PythonSnips/blob/master/datastructures/linked_lists/circular/node.py)
+      * [Test Circular Linked List](https://github.com/BrianLusina/PythonSnips/blob/master/datastructures/linked_lists/circular/test_circular_linked_list.py)
     * Doubly Linked List
       * [Test Doubly Linked List](https://github.com/BrianLusina/PythonSnips/blob/master/datastructures/linked_lists/doubly_linked_list/test_doubly_linked_list.py)
       * [Test Doubly Linked List Move Tail To Head](https://github.com/BrianLusina/PythonSnips/blob/master/datastructures/linked_lists/doubly_linked_list/test_doubly_linked_list_move_tail_to_head.py)