Added circleci badge. Fixed style of other badge.

Author: patcon

README.md

@@ -2,8 +2,9 @@
 
 [![GitHub](https://img.shields.io/badge/project-Data_Together-487b57.svg?style=flat-square)](http://github.com/datatogether)
 [![Slack](https://img.shields.io/badge/slack-Archivers-b44e88.svg?style=flat-square)](https://archivers-slack.herokuapp.com/)
-[![License](https://img.shields.io/github/license/datatogether/coverage.svg)](./LICENSE)
+[![License](https://img.shields.io/github/license/datatogether/coverage.svg?style=flat-square)](./LICENSE)
 [![Codecov](https://img.shields.io/codecov/c/github/datatogether/coverage.svg?style=flat-square)](https://codecov.io/gh/datatogether/coverage)
+[![CircleCI](https://img.shields.io/circleci/project/github/datatogether/coverage.svg?style=flat-square)](https://circleci.com/gh/datatogether/coverage)
 
 Visualization to display "archival coverage," starting with epa.gov. This takes a list of urls and associated archiving information, and turns that into a tree of url paths with associated coverage information.