Docs: Add blog post links

Author: nzakas

README.md

@@ -58,6 +58,8 @@ These are the most recent blog posts covering the most recent version of the cod
 ### Data Structures
 
 * [Linked List](https://humanwhocodes.com/blog/2019/01/computer-science-in-javascript-linked-list/)
+* [Doubly-Linked List](https://humanwhocodes.com/blog/2019/02/computer-science-in-javascript-doubly-linked-lists/)
+* [Circular Doubly-Linked List](https://humanwhocodes.com/blog/2019/03/computer-science-in-javascript-circular-doubly-linked-lists/)
 
 ## Original Blog Posts
 

src/data-structures/circular-doubly-linked-list/README.md

@@ -13,6 +13,8 @@ A JavaScript implementation of a circular doubly linked list. This class uses th
 1. Defining a `values()` generator method.
 1. Returning `undefined` from `get()` when no such index exists.
 
+Read the [blog post](https://humanwhocodes.com/blog/2019/03/computer-science-in-javascript-circular-doubly-linked-lists/) about the design of this class.
+
 ## Usage
 
 Use CommonJS to get access to the `CircularDoublyLinkedList` constructor:

src/data-structures/doubly-linked-list/README.md

@@ -13,6 +13,8 @@ A JavaScript implementation of a doubly linked list. This class uses the convent
 1. Defining a `values()` generator method.
 1. Returning `undefined` from `get()` when no such index exists.
 
+Read the [blog post](https://humanwhocodes.com/blog/2019/02/computer-science-in-javascript-doubly-linked-lists/) about the design of this class.
+
 ## Usage
 
 Use CommonJS to get access to the `DoublyLinkedList` constructor: