Math extension has Selenium tests

Change-Id: I453b5a5cffe1f186efd293dbef13e4a87d299bc2

README.md

@@ -99,6 +99,7 @@ Repositories that use the gem:
 1. CirrusSearch: [Gerrit](https://gerrit.wikimedia.org/r/#/admin/projects/mediawiki/extensions/CirrusSearch), [GitHub](https://github.com/wikimedia/mediawiki-extensions-CirrusSearch), [Code Climate](https://codeclimate.com/github/wikimedia/mediawiki-extensions-CirrusSearch)
 1. ContentTranslation: [Gerrit](https://gerrit.wikimedia.org/r/#/admin/projects/mediawiki/extensions/ContentTranslation), [GitHub](https://github.com/wikimedia/mediawiki-extensions-ContentTranslation), [Code Climate](https://codeclimate.com/github/wikimedia/mediawiki-extensions-ContentTranslation)
 1. Flow: [Gerrit](https://gerrit.wikimedia.org/r/#/admin/projects/mediawiki/extensions/Flow), [GitHub](https://github.com/wikimedia/mediawiki-extensions-Flow), [Code Climate](https://codeclimate.com/github/wikimedia/mediawiki-extensions-Flow)
+1. Math: [Gerrit](https://gerrit.wikimedia.org/r/#/admin/projects/mediawiki/extensions/Math), [GitHub](https://github.com/wikimedia/mediawiki-extensions-Math), [Code Climate](https://codeclimate.com/github/wikimedia/mediawiki-extensions-Math)
 1. MediaWiki: [Gerrit](https://gerrit.wikimedia.org/r/#/admin/projects/mediawiki/core), [GitHub](https://github.com/wikimedia/mediawiki-core), [Code Climate](https://codeclimate.com/github/wikimedia/mediawiki-core)
 1. MobileFrontend: [Gerrit](https://gerrit.wikimedia.org/r/#/admin/projects/mediawiki/extensions/MobileFrontend), [GitHub](https://github.com/wikimedia/mediawiki-extensions-MobileFrontend), [Code Climate](https://codeclimate.com/github/wikimedia/mediawiki-extensions-MobileFrontend)
 1. MultimediaViewer: [Gerrit](https://gerrit.wikimedia.org/r/#/admin/projects/mediawiki/extensions/MultimediaViewer), [GitHub](https://github.com/wikimedia/mediawiki-extensions-MultimediaViewer), [Code Climate](https://codeclimate.com/github/wikimedia/mediawiki-extensions-MultimediaViewer)