Add FormAssembly Provider

Author: FatherShawn

docs/providers/thirdparty.md

@@ -44,6 +44,7 @@ Gateway | Composer Package | Maintainer
 [Envato](https://github.com/dilab/envato-oauth2-provider) | dilab/envato-oauth2-provider | [Xu Ding](https://github.com/dilab)
 [Eventbrite](https://github.com/stevenmaguire/oauth2-eventbrite) | stevenmaguire/oauth2-eventbrite | [Steven Maguire](https://github.com/stevenmaguire)
 [Fitbit](https://github.com/djchen/oauth2-fitbit) | djchen/oauth2-fitbit | [Dan Chen](https://github.com/djchen)
+[FormAssembly](https://github.com/FatherShawn/oauth2-formassembly) | fathershawn/oauth2-formassembly | [Shawn Duncan](https://github.com/FatherShawn)
 [Foursquare](https://github.com/stevenmaguire/oauth2-foursquare) | stevenmaguire/oauth2-foursquare | [Steven Maguire](https://github.com/stevenmaguire)
 [FreeAgent](https://github.com/CloudManaged/oauth2-freeagent) | cloudmanaged/oauth2-freeagent | [Israel Sotomayor](https://github.com/zot24)
 [GitLab](https://github.com/omines/oauth2-gitlab) | omines/oauth2-gitlab | [Niels Keurentjes](https://github.com/curry684)