Add Wal-Mart

README.md

@@ -549,6 +549,7 @@ API | Description | Auth | HTTPS | Link |
 API | Description | Auth | HTTPS | Link |
 |---|---|---|---|---|
 | eBay | Sell and Buy on eBay | `OAuth` | Yes | [Go!](https://go.developer.ebay.com/) |
+| Wal-Mart | Item price and availability | `apiKey` | Yes | [Go!](https://developer.walmartlabs.com/docs) |
 
 ### Social
 API | Description | Auth | HTTPS | Link |