Update CHANGELOG.md for 9.5.6

[ci skip]

CHANGELOG.md

@@ -2,6 +2,13 @@
 documentation](doc/development/changelog.md) for instructions on adding your own
 entry.
 
+## 9.5.6 (2017-09-29)
+
+- [FIXED] Fix MR ready to merge buttons/controls at mobile breakpoint. !14242
+- [FIXED] Fix errors thrown in merge request widget with external CI service/integration.
+- [FIXED] Update x/x discussions resolved checkmark icon to be green when all discussions resolved.
+- [FIXED] Fix 500 error on merged merge requests when GitLab is restored from a backup.
+
 ## 9.5.5 (2017-09-18)
 
 - [SECURITY] Upgrade mail and nokogiri gems due to security issues. !13662 (Markus Koller)

changelogs/unreleased/33287-fix-mr-widget-errors-with-external-services.yml

----
-title: Fix errors thrown in merge request widget with external CI service/integration
-merge_request:
-author:
-type: fixed

changelogs/unreleased/37259-some-mr-ready-mobile-fixes.yml

----
-title: Fix MR ready to merge buttons/controls at mobile breakpoint
-merge_request: 14242
-author:
-type: fixed

changelogs/unreleased/37465-fix-line-resolve-all-green-checkmark-icon.yml

----
-title: Update x/x discussions resolved checkmark icon to be green when all discussions
-  resolved
-merge_request:
-author:
-type: fixed

changelogs/unreleased/38319-nomethoderror-undefined-method-sha-for-nil-nilclass.yml

----
-title: Fix 500 error on merged merge requests when GitLab is restored from a backup
-merge_request:
-author:
-type: fixed