changelog: add notes about closing #15189

CHANGELOG.md

@@ -10,6 +10,10 @@
 * **Annotations**: Support PATCH verb in annotations http api [#12546](https://github.com/grafana/grafana/issues/12546), thx [@SamuelToh](https://github.com/SamuelToh)
 * **Templating**: Add json formatting to variable interpolation [#15291](https://github.com/grafana/grafana/issues/15291), thx [@mtanda](https://github.com/mtanda)
 
+### 6.6.0-beta1 fixes
+
+* **Postgres**: Fix default port not added when port not configured [#15189](https://github.com/grafana/grafana/issues/15189)
+
 # 6.0.0-beta1 (2019-01-30)
 
 ### New Features