Update README.md

Author: sdgluck

README.md

@@ -8,5 +8,6 @@
 - Generates example library code for setting headers, e.g. nginx, express, & others
 - Share header configurations via shareable URLs (e.g. [public + max-age 2 days](https://cache-control.sdgluck.now.sh/?s=W3sibmFtZSI6InB1YmxpYyIsImFyZyI6bnVsbCwidGltZSI6InNlY3MifSx7Im5hbWUiOiJtYXgtYWdlIiwiYXJnIjoiMiIsInRpbWUiOiJkYXlzIn1d))
 - Header descriptions taken from [MDN](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control)
+- Inspired by [Cache-Control for Civilians](https://csswizardry.com/2019/03/cache-control-for-civilians/)
 
 <img src="https://raw.githubusercontent.com/sdgluck/cache-control/master/screenshot.jpg" />