Update README.md

README.md

@@ -7,6 +7,7 @@ crowi-plus
 
 [![wercker status](https://app.wercker.com/status/39cdc49d067d65c39cb35d52ceae6dc1/s/master "wercker status")](https://app.wercker.com/project/byKey/39cdc49d067d65c39cb35d52ceae6dc1)
 [![dependencies status](https://david-dm.org/weseek/crowi-plus.svg)](https://david-dm.org/weseek/crowi-plus)
+[![docker build automated](https://img.shields.io/docker/automated/jrottenberg/ffmpeg.svg)](https://hub.docker.com/r/weseek/crowi-plus/)
 [![MIT License](http://img.shields.io/badge/license-MIT-blue.svg?style=flat)](LICENSE)
 [![Join the chat at https://gitter.im/weseek/crowi-plus](https://badges.gitter.im/weseek/crowi-plus.svg)](https://gitter.im/weseek/crowi-plus?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)