Added IFTTT plugin documentation

Plugins.md

@@ -24,6 +24,7 @@
 * [MIDI plugin](#midi-plugin)
 * [MQTT plugin](#mqtt-plugin)
 * [Pushbullet plugin](#pushbullet-plugin)
+* [IFTTT plugin](#ifttt-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.
@@ -785,6 +786,39 @@ curl -XPOST -H 'Content-Type: application/json' \
     http://hostname:8008/execute
 ```
 
+# IFTTT plugin
+
+[Plugin reference](https://platypush.readthedocs.io/en/latest/platypush/plugins/ifttt.html)
+
+[IFTTT](https://ifttt.com) is a very versatile cloud service to automate tasks and trigger actions on particular events. IFTTT comes with some channels that may not be available on Platypush (e.g. trigger events on your Android or iOS device, send Telegram messages, create Trello tasks etc.), or you've been an IFTTT user already and you might want to integrate Platypush with your existing IFTTT configuration.
+
+You can use Platypush to trigger IFTTT events using the [Maker API](https://ifttt.com/maker_webhooks).
+
+Steps:
+
+1. Click on the link above and sign in with your IFTTT account
+
+2. Click on _Documentation_ and copy the key associated to your account
+
+3. Configure the Platypush plugin:
+
+```yaml
+ifttt:
+    ifttt_key: YOUR_KEY
+```
+
+4. In this example suppose that you want to automatically send a Telegram message to yourself with some content. Create an IFTTT applet having _Webhooks_ as a trigger channel and specify `telegram_send` as `event_name`
+
+5. Specify Telegram as action channel and select the "Send message" action. Specify your own number and select the ingredient `value1` as body
+
+6. Start Platypush and try to send a message to yourself:
+
+```shell
+curl -XPOST -H 'Content-Type: application/json' \
+    -d '{"type":"request", "target":"hostname", "action":"ifttt.trigger_event", "args": {"event_name":"telegram_send", "values":["IT WORKED"]}}' \
+    http://hostname:8008/execute
+```
+
 # Weather plugin
 
 [Plugin reference](https://platypush.readthedocs.io/en/latest/platypush/plugins/weather.html)