Bump to RN 0.47 add rn-config

Note: You need to cp env-example to .env and run yarn

README.md

@@ -1,6 +1,7 @@
 ## Install
     # See https://facebook.github.io/react-native/docs/getting-started.html#content
     yarn
+    cp env-example .env
     react-native start
     react-native run-android