Add Reason Conf to readme (#559)

* Update README.md for Reason Conf

* Update README.md

Author: Dylan Irlbeck

README.md

@@ -1,3 +1,8 @@
+**🎟 [Reason Conf US](https://www.reason-conf.us) is happening October 7-8th in Chicago 🎉**  
+Buy tickets or sponsor the event by visiting [https://www.reason-conf.us](https://www.reason-conf.us)
+
+---
+
 # Reason bindings for React Native
 
 [![Build Status](https://img.shields.io/circleci/project/github/reasonml-community/reason-react-native/master.svg)](https://circleci.com/gh/reasonml-community/reason-react-native)