[AIRFLOW-579] Mention BlaBlaCar as Airflow user[]

Closes apache#1840 from wmorin/feat-mention-blablacar-
as-user

README.md

@@ -87,6 +87,7 @@ Currently **officially** using Airflow:
 1. [Apigee](https://apigee.com) [[@btallman](https://github.com/btallman)]
 1. [Auth0](https://auth0.com) [[@sicarul](https://github.com/sicarul)]
 1. [Bellhops](https://github.com/bellhops)
+1. [BlaBlaCar](https://www.blablacar.com) [[@puckel](https://github.com/puckel) & [@wmorin](https://github.com/wmorin)]
 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)]