Update CHANGELOG.md for 9.1.5

CHANGELOG.md

@@ -2,6 +2,12 @@
 documentation](doc/development/changelog.md) for instructions on adding your own
 entry.
 
+## 9.1.5 (2017-05-31)
+
+- Move uploads from 'public/uploads' to 'public/uploads/system'.
+- Restrict API X-Frame-Options to same origin.
+- Allow users autocomplete by author_id only for authenticated users.
+
 ## 9.1.4 (2017-05-12)
 
 - No changes.

changelogs/unreleased/28917-contain-uploads-in-system-dir.yml

----
-title: Move uploads from 'public/uploads' to 'public/uploads/system'
-merge_request:
-author:

changelogs/unreleased/dz-api-x-frame.yml

----
-title: Restrict API X-Frame-Options to same origin
-merge_request:
-author:

changelogs/unreleased/dz-restrict-autocomplete.yml

----
-title: Allow users autocomplete by author_id only for authenticated users
-merge_request:
-author: