Prepping for 1.6 release.

Adds release notes and edits/revises new Compose in production doc.

docs/index.md

@@ -5,6 +5,8 @@ page_keywords: documentation, docs,  docker, compose, orchestration, containers
 
 # Docker Compose
 
+## Overview
+
 Compose is a tool for defining and running complex applications with Docker.
 With Compose, you define a multi-container application in a single file, then
 spin your application up in a single command which does everything that needs to
@@ -191,3 +193,17 @@ At this point, you have seen the basics of how Compose works.
   [Rails](rails.md), or [Wordpress](wordpress.md).
 - See the reference guides for complete details on the [commands](cli.md), the
   [configuration file](yml.md) and [environment variables](env.md).
+  
+## Release Notes
+
+### Version 1.2.0 (April 7, 2015)
+
+For complete information on this release, see the [1.2.0 Milestone project page](https://github.com/docker/compose/wiki/1.2.0-Milestone-Project-Page).
+In addition to bug fixes and refinements, this release adds the following:
+
+* The `extends` keyword, which adds the ability to extend services by sharing  common configurations. For details, see
+[PR #972](https://github.com/docker/compose/pull/1088).
+
+* Better integration with Swarm. Swarm will now schedule inter-dependent
+containers on the same host. For details, see
+[PR #972](https://github.com/docker/compose/pull/972).