Added Ring Camera component documentation and added new sensors (#3682)

* Added Ring Camera component documentation and added new sensors

* Kept only the basic as example for the component

* Added scan_interval option to camera ring documentation

* Rephrased statement

source/_components/camera.ring.markdown

@@ -0,0 +1,33 @@
+---
+layout: page
+title: "Ring Binary Camera"
+description: "Instructions on how to integrate your Ring.com devices within Home Assistant."
+date: 2017-10-20 10:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: ring.png
+ha_category: Camera
+ha_release: 0.57
+ha_iot_class: "Cloud Polling"
+---
+
+To get your [Ring.com](https://ring.com/) cameras working within Home Assistant, please follow the instructions for the general [Ring component](/components/ring).
+
+Once you have enabled the [Ring component](/components/ring), add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+camera:
+  - platform: ring
+```
+
+Configuration variables:
+
+- **ffmpeg_arguments**: (*Optional*): Extra options to pass to ffmpeg, e.g., image quality or video filter options.
+- **scan_interval**: (*Optional*): How frequently to query for new video. Defaults to 90 seconds.
+
+**Note:** To be able to playback the last capture, it is required to install the `ffmpeg` component. Make sure to follow the steps mentioned at [FFMPEG](https://home-assistant.io/components/ffmpeg/) documentation.
+
+Currently it supports doorbell and stickup cameras.