docs: add status badges

Author: Tom Kirkpatrick

Diff for: README.md

@@ -3,6 +3,8 @@ CHANGED
 
 [![Greenkeeper badge](https://badges.greenkeeper.io/fullcube/loopback-ds-changed-mixin.svg)](https://greenkeeper.io/)
 
+[![Circle CI](https://circleci.com/gh/fullcube/loopback-ds-changed-mixin.svg?style=svg)](https://circleci.com/gh/fullcube/loopback-ds-changed-mixin) [![Coverage Status](https://coveralls.io/repos/github/fullcube/loopback-ds-changed-mixin/badge.svg?branch=master)](https://coveralls.io/github/fullcube/loopback-ds-changed-mixin?branch=master) [![Dependencies](http://img.shields.io/david/fullcube/loopback-ds-changed-mixin.svg?style=flat)](https://david-dm.org/fullcube/loopback-ds-changed-mixin) [![semantic-release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg)](https://github.com/semantic-release/semantic-release)
+
 This module is designed for the [Strongloop Loopback](https://github.com/strongloop/loopback) framework.
 It provides a mixin that makes it possible to trigger a function if selected
 model properties change.