tello: add Tello drone to list of supported platforms

Signed-off-by: Ron Evans <[email protected]>

README.md

@@ -194,6 +194,7 @@ Gobot has a extensible system for connecting to hardware devices. The following
 - [C.H.I.P](http://www.nextthing.co/pages/chip) <=> [Package](https://github.com/hybridgroup/gobot/tree/master/platforms/chip)
 - [C.H.I.P Pro](https://docs.getchip.com/chip_pro.html) <=> [Package](https://github.com/hybridgroup/gobot/tree/master/platforms/chip)
 - [Digispark](http://digistump.com/products/1) <=> [Package](https://github.com/hybridgroup/gobot/tree/master/platforms/digispark)
+- [DJI Tello](https://www.ryzerobotics.com/tello) <=> [Package](https://github.com/hybridgroup/gobot/tree/master/platforms/dji/tello)
 - [DragonBoard](https://developer.qualcomm.com/hardware/dragonboard-410c) <=> [Package](https://github.com/hybridgroup/gobot/tree/master/platforms/dragonboard)
 - [ESP8266](http://esp8266.net/) <=> [Package](https://github.com/hybridgroup/gobot/tree/master/platforms/firmata)
 - [GoPiGo 3](https://www.dexterindustries.com/gopigo3/) <=> [Package](https://github.com/hybridgroup/gobot/tree/master/platforms/dexter/gopigo3)