Merge pull request #499 from shadowhand/feature/add-untappd-provider

Add Untappd provider

README.PROVIDERS.md

@@ -70,6 +70,7 @@ Gateway | Composer Package | Maintainer
 [Square](https://packagist.org/packages/wheniwork/oauth2-square) | wheniwork/oauth2-square | [Woody Gilk](https://github.com/shadowhand)
 [Twitch.tv](https://github.com/tpavlek/oauth2-twitch) | depotwarehouse/oauth2-twitch | [Troy Pavlek](https://github.com/tpavlek)
 [Uber](https://github.com/stevenmaguire/oauth2-uber) | stevenmaguire/oauth2-uber | [Steven Maguire](https://github.com/stevenmaguire)
+[Untappd](https://github.com/shadowhand/oauth2-untappd) | shadowhand/oauth2-untappd | [Woody Gilk](https://github.com/shadowhand)
 [Vend](https://github.com/wheniwork/oauth2-vend) | wheniwork/oauth2-vend | [When I Work](https://github.com/wheniwork)
 [Vkontakte](https://github.com/j4k/oauth2-vkontakte) | j4k/oauth2-vkontakte | [Jack W](https://github.com/j4k)
 [Yahoo](https://packagist.org/packages/hayageek/oauth2-yahoo) | hayageek/oauth2-yahoo | [Ravishanker Kusuma](https://github.com/hayageek)