update readme with dashboard screenshot and v2 info

Author: nothans

README.md

@@ -1,12 +1,15 @@
 # IoT Debugger
-Use this web-based tool to see data stored in an Internet of Things data service such as [ThingSpeak](https://thingspeak.com/channels/9).
+Use this web-based tool to see data stored in an Internet of Things data service such as [ThingSpeak](https://thingspeak.com/channels/9) and [Adafruit IO](https://io.adafruit.com/).
+
+![IoT Debugger Dashboard](app/screenshot-dashboard.png)
 
 ## Demo
-* [Open Demo App for ThingSpeak](https://iot-debugger.nothans.com/app/index.html)
+* [Open Demo App](https://iot-debugger.nothans.com/app/index.html)
 * Click play button to start getting data
 
 ## How to Use IoT Debugger
 * Download project
 * Open index.html in a browser tab
-* Select ThingSpeak
-* To use ThingSpeak - Enter the ThingSpeak Channel and Read API Key and click the play button to start getting data
+* **Dashboard** - Monitor multiple ThingSpeak channels and Adafruit IO feeds at a glance
+* **ThingSpeak** - Enter the ThingSpeak Channel and Read API Key and click the play button to start getting data
+* **Adafruit IO** - Enter the Username, Feed Key, and API Key and click the play button to start getting data