update the readme

Readme.md

@@ -1,3 +1,8 @@
-Garnish
+Garnish - simple varnish implementation written in Go
 ===
 
+Garnish is an example of a simple varnish implementation which should demonstrate.
+
+It supports only `Cache-Control` header and keeps all the data in memory. It means that after restart of the application all data will disappear.
+
+The project was described in more details in [the article](https://developer20.com/garnish-simple-varnish-in-go/).