Move changelog to GitHub, add badges for the plugin site and release …

…stats

README.md

@@ -1,6 +1,10 @@
 Docker Pipeline Plugin
 =====================================
 
+[![Jenkins Plugin](https://img.shields.io/jenkins/plugin/v/docker-workflow.svg)](https://plugins.jenkins.io/docker-workflow)
+[![GitHub release](https://img.shields.io/github/release/jenkinsci/docker-workflow-plugin.svg?label=changelog)](https://github.com/jenkinsci/docker-workflow-plugin/releases/latest)
+[![Jenkins Plugin Installs](https://img.shields.io/jenkins/plugin/i/docker-workflow.svg?color=blue)](https://plugins.jenkins.io/docker-workflow)
+
 Jenkins plugin which allows building, testing, and using Docker images from Jenkins Pipeline projects.
 
 Summary
@@ -33,3 +37,9 @@ to sanity check, then
 License
 ---
 [MIT License](http://opensource.org/licenses/MIT)
+
+Changelog
+---
+
+* For new versions, see [GitHub Releases](https://github.com/jenkinsci/docker-workflow-plugin/releases)
+* For versions 1.19 and older, see the [plugin's Wiki page](https://wiki.jenkins.io/display/JENKINS/Docker+Pipeline+Plugin)