Updated Ring component documentation (#2366)

* Updated Ring component documentation

* Add reference to sub pages

source/_components/ring.markdown

@@ -0,0 +1,33 @@
+---
+layout: page
+title: "Ring"
+description: "Instructions on how to integrate your Ring.com devices within Home Assistant."
+date: 2017-04-01 10:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: ring.png
+ha_category: Hub
+ha_release: 0.42
+---
+
+The `ring` implementation allows you to integrate your [Ring.com](https://ring.com/) devices in Home Assistant.
+
+Currently only doorbells are supported by this sensor.
+
+To enable device linked in your [Ring.com](https://ring.com/) account, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+ring:
+  username: you@example.com
+  password: secret
+```
+
+Configuration variables:
+
+- **username** (*Required*): The username for accessing your Ring account.
+- **password** (*Required*): The password for accessing your Ring account.
+
+Finish its configuration by visiting the [Ring binary_sensor page](/components/binary_sensor.ring/) or [Ring sensor page](/components/sensor.ring/).