Update CHANGELOG.md

Author: cldougl

Diff for: CHANGELOG.md

@@ -2,6 +2,11 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Unreleased]
+### Added
+- Plot configuration options for offline plots. See the list of [configuration options](https://github.com/Rikorose/plotly.py/blob/master/plotly/offline/offline.py#L189) and [examples](https://plot.ly/javascript/configuration-options/) for more information. 
+	- Please note that these configuration options are for offline plots ONLY. For configuration options when embedding online plots please see our [embed tutorial](http://help.plot.ly/embed-graphs-in-websites/#step-8-customize-the-iframe).  
+
 ## [1.12.9] - 2016-08-22
 ### Fixed
 - the colorbar in `.create_trisurf` now displays properly in `offline mode`.