Update the readme.

Author: andersio

README.md

@@ -1,11 +1,12 @@
 ## ReactiveCollections
 This project is the staging ground of collection operators and collection view bindings for ReactiveSwift and ReactiveCocoa.
 
-### Primary goals
-1. Collection diffing operators (flat & sectioned).
-1. Defining a collection changeset and snapshot format.
-1. Convenience for applying a snapshot to collection views.
+## Diffing
+The collection differ is now offered separately as [FlexibleDiff](https://github.com/RACCommunity/FlexibleDiff).
 
-### Secondary goals
-1. Complete collection view binding solutions.
-1. Reactive collection types.
+### Goals
+1. [x] Defining a collection changeset and snapshot format.
+1. [x] Collection diffing operators (flat & sectioned).
+1. [ ] Convenience for applying a snapshot to collection views.
+1. [ ] Complete collection view binding solutions.
+1. [ ] Reactive collection types.