README.md: Add Freenode IRC badge

Join #picocms on irc.freenode.net via irc://irc.freenode.net/picocms or https://webchat.freenode.net/?channels=%23picocms

README.md

@@ -4,6 +4,7 @@ Pico
 [![License](https://picocms.github.io/Pico/badges/pico-license.svg)](https://github.com/picocms/Pico/blob/master/LICENSE.md)
 [![Version](https://picocms.github.io/Pico/badges/pico-version.svg)](https://github.com/picocms/Pico/releases/latest)
 [![Build Status](https://api.travis-ci.org/picocms/Pico.svg)](https://travis-ci.org/picocms/Pico)
+[![Freenode IRC Webchat](https://picocms.github.io/Pico/badges/pico-chat.svg)](https://webchat.freenode.net/?channels=%23picocms)
 [![Tweet Button](https://cloud.githubusercontent.com/assets/640217/11483728/b0842918-976f-11e5-9185-d53261b3125b.png)](https://twitter.com/intent/tweet?text=Pico+is+a+stupidly+simple%2C+blazing+fast%2C+flat+file+CMS.+Visit+http%3A%2F%2Fpicocms.org+and+downlaod+%23picocms+today%21+via+%40gitpicocms&related=gitpicocms)
 
 Pico is a stupidly simple, blazing fast, flat file CMS. See http://picocms.org/ for more info.