Update README.md

Author: FrangSierra

README.md

@@ -29,6 +29,7 @@ Library provides set of static methods of classes:
 * RxFirebaseDatabase
 * RxFirebaseStorage
 * RxFirestore
+* RxFirebaseFunctions
 
 It also provides a custom implementation of `FirebaseRecyclerAdapter`:
 * RxFirebaseRecyclerAdapter
@@ -307,4 +308,4 @@ You can check all the differences between RxJava and RxJava 2.0 in the next [Lin
 ## Support on Beerpay
 Hey dude! Help me out for a couple of :beers:!
 
-[![Beerpay](https://beerpay.io/FrangSierra/RxFirebase/badge.svg?style=beer-square)](https://beerpay.io/FrangSierra/RxFirebase)  [![Beerpay](https://beerpay.io/FrangSierra/RxFirebase/make-wish.svg?style=flat-square)](https://beerpay.io/FrangSierra/RxFirebase?focus=wish)
+[![Beerpay](https://beerpay.io/FrangSierra/RxFirebase/badge.svg?style=beer-square)](https://beerpay.io/FrangSierra/RxFirebase)  [![Beerpay](https://beerpay.io/FrangSierra/RxFirebase/make-wish.svg?style=flat-square)](https://beerpay.io/FrangSierra/RxFirebase?focus=wish)