Update README travis url from auto generated url (#14)

* Update travis url from auto generated url

* Update README travis_img url

Author: shum

README.md

@@ -28,8 +28,8 @@ Apache 2.0
 
 [![][gitter_img]][gitter_url]
 
-[travis_img]: https://secure.travis-ci.org/mongodb-js/mongodb-database-model.svg?branch=master
-[travis_url]: https://travis-ci.org/mongodb-js/mongodb-database-model
+[travis_img]: https://secure.travis-ci.org/mongodb-js/database-model.svg?branch=master
+[travis_url]: https://travis-ci.org/mongodb-js/database-model
 [npm_img]: https://img.shields.io/npm/v/mongodb-database-model.svg
 [npm_url]: https://www.npmjs.org/package/mongodb-database-model
 [gitter_img]: https://badges.gitter.im/Join%20Chat.svg