update docs

CHANGES.md

@@ -1,9 +1,11 @@
 CHANGES
 ========
 
-## 3.1.1
+## 3.1.1-RC
 
 * Improvement: Add 'future' theme
+* Improvement: List up pages which restricted for Group ACL
+* Fix: PageGroupRelation didn't remove when page is removed completely
 
 
 ## 3.1.0