add www.aslezak.com to showcase (#3878)

Author: amslezak

README.md

@@ -152,6 +152,8 @@ Websites built with Gatsby:
 * [ERC dEX](https://ercdex.com)
 * [iContract Blog](https://blog.icontract.co.uk)
 * [Dona Rita](https://donarita.co.uk) ([source](https://github.com/peduarte/dona-rita-website))
+* [Andy Slezak](https://www.aslezak.com) ([source](https://github.com/amslezak))
+
 
 ## Docs