Add 1.0.0 release to changelog.

CHANGELOG.md

@@ -1,5 +1,18 @@
 # Changelog
 
+## 1.0.0 (2017-10-18)
+
+This is the first stable release of `recoil/react`. There have been no changes
+to the API since the `1.0.0-alpha.2` release. This package is being used in
+production systems.
+
+Please note that although this version is based on a "pre-release" tag of
+[`react/event-loop`](https://github.com/reactphp/event-loop), the event loop has
+been stable for a long time. The [v1 roadmap](https://github.com/reactphp/event-loop/issues/101)
+for `react/event-loop` will likely introduce some BC breaks, however this should
+not prevent future `recoil/react` versions from adhering to
+[`recoil/api`](https://github.com/recoilphp/api) v1.
+
 ## 1.0.0-alpha.2 (2017-01-10)
 
 - **[NEW]** Add `select()` API operation