README.md add
README.md add

RNT17/FriendlyChat-Android-Codelab,RNT17/FriendlyChat-Android-Codelab,RNT17/FriendlyChat-Android-Codelab,RNT17/FriendlyChat-Android-Codelab,RNT17/FriendlyChat-Android-Codelab