Generate an ERD with three tables

I should probably explain more. I chose to mock up a simple database for a blog. Articles represent a blog post and articles can have comments. Comments can also have comments. The only real difference between the articles and comments is the fact the article has a title and allows more characters in the body.

My project is going to be based on a company I used to work with that would create photo ID cards for various businesses. The entities I chose to work with: customerID, IDCard, and Orders. Each of these entities are connected by a many-to-many relationship.

I have chosen three tables. Users, Articles, and Comments. Users has a one to many relationship with articles and comments so both the Articles and Comments table use the userID as a foreign key. Articles has a one to many relationship with comments so the Comments table uses the articleID as a foreign key. Comments are nested in the style of an adjacency table so the Comments table references its own commentID using the parentID column.

erd link:

I work at a warehouse distributor and have chosen to use this as the basis for my project. To start with, I've limited myself to 3 tables--Orders, Products, and Customers. OrderNumber, ItemNumber, and CustomerID are the primary keys for each table respectively. Each of these keys identify each entry uniquely, and can easily be swung around between the tables to borrow information.

Here is my ERD:
https://drive.google.com/open?id=0B5hBlRd1P7vEaTJDc2pmVW8yRTg