[AIRFLOW-650] Adding Celect to user list

Closes apache#1901 from superdosh/master

README.md

@@ -93,6 +93,7 @@ Currently **officially** using Airflow:
 1. [Bloc](https://www.bloc.io) [[@dpaola2](https://github.com/dpaola2)]
 1. BlueApron [[@jasonjho](https://github.com/jasonjho) & [@matthewdavidhauser](https://github.com/matthewdavidhauser)]
 1. [Blue Yonder](http://www.blue-yonder.com) [[@blue-yonder](https://github.com/blue-yonder)]
+1. [Celect](http://www.celect.com) [[@superdosh](https://github.com/superdosh) & [@chadcelect](https://github.com/chadcelect)]
 1. [Clairvoyant](https://clairvoyantsoft.com) [@shekharv](https://github.com/shekharv)
 1. [Clover Health](https://www.cloverhealth.com) [[@gwax](https://github.com/gwax) & [@vansivallab](https://github.com/vansivallab)]
 1. Chartboost [[@cgelman](https://github.com/cgelman) & [@dclubb](https://github.com/dclubb)]