Added Adafruit IO plugin doc to the wiki

Plugins.md

@@ -25,6 +25,7 @@
 * [MQTT plugin](#mqtt-plugin)
 * [Pushbullet plugin](#pushbullet-plugin)
 * [IFTTT plugin](#ifttt-plugin)
+* [Adafruit IO plugin](#adafruit-io-plugin)
 * [Weather plugin](#weather-plugin)
 
 A couple of plugins are available out of the box with Platypush under `plugins/`. Some of them may require extra Python or system dependencies. This page will show you some of the available plugins and some possible use cases, although the only real limit to how to connect things together is just your own imagination. This is not intended to be a complete reference of all the available plugins with their supported methods and dependencies, please refer to our [ReadTheDocs](https://platypush.readthedocs.io/en/latest/plugins.html) page for a more complete reference.
@@ -819,6 +820,38 @@ curl -XPOST -H 'Content-Type: application/json' \
     http://hostname:8008/execute
 ```
 
+# Adafruit IO plugin
+
+[Plugin reference](https://platypush.readthedocs.io/en/latest/platypush/plugins/adafruit-io.html)
+
+[Adafruit IO](https://io.adafruit.com) is a message-based cloud storage for numerical values. You can use it to store reads from your sensors, see the values on the Adafruit dashboard wherever you are, trigger IFTTT rules if a value goes below or above a threshold and so on.
+
+First create an account on Adafruit and get your key from [Adafruit IO](https://io.adafruit.com). Then configure the Platypush plugin:
+
+```yaml
+adafruit.io:
+    username: your_user
+    key: your_key
+```
+
+Then you can create a feed on the web interface and configure for instance an event hook that forwards a new read from your temperature sensor to your remote feed:
+
+```yaml
+event.hook.OnSensorData:
+    if:
+        type: platypush.message.event.sensor.SensorDataChangeEvent
+    then:
+        action: procedure.OnSensorData
+
+procedure.sync.OnSensorData:
+    - if ${'temperature' in data}:
+        -
+            action: adafruit.io.send
+            args:
+                feed: temperature
+                value: ${data.get('temperature')}
+```
+
 # Weather plugin
 
 [Plugin reference](https://platypush.readthedocs.io/en/latest/platypush/plugins/weather.html)