document the matrix notification platform (#1215)

source/_components/notify.matrix.markdown

@@ -0,0 +1,39 @@
+---
+layout: page
+title: "Matrix"
+description: "Instructions how to add Matrix notifications to Home Assistant."
+date: 2016-10-11 23:51
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: matrix.png
+ha_category: Notifications
+ha_release: 0.31
+---
+
+
+The `matrix` platform allows you to deliver notifications from Home Assistant to a Matrix room. Rooms can be both direct as well as group chats.
+
+```yaml
+# Example configuration.yaml entry
+notify:
+  - platform: matrix
+    homeserver: HOMESERVER
+    username: USERNAME
+    password: PASSWORD
+    default_room: ROOM_ID_OR_ALIAS
+```
+
+Configuration variables:
+
+- **name** (*Optional*): Setting the optional parameter `name` allows multiple notifiers to be created. The default value is `notify`. The notifier will bind to the service `notify.NOTIFIER_NAME`.
+- **homeserver** (*Required*): The base URL of the homeserver, where the notifier account is registered (e.g. `https://matrix.org`).
+- **username** (*Required*): The username of the notifying Matrix account.
+- **password** (*Required*): The password for the given Matrix account.
+- **default_room** (*Required*): The room all messages will be sent to, when no other target is given.
+- **verify_ssl** (*Optional*): Verify the homeservers certificate. Defaults to `true`.
+
+The target room has to be precreated, the room id can be obtained from the rooms settings dialog. Rooms by default have a canonical id of the form `!<randomid>:homeserver.tld`, but can also be allocated aliases like `#roomname:homeserver.tld`. The notifying account may need to be invited to the room, depending on the individual rooms policies.
+
+To use notifications, please see the [getting started with automation page](/getting-started/automation/).