DoorBird (#3147)

* Add documentation for DoorBird components

* Update release to 0.52

* Update example configurations

* Update doorbird.markdown

* Update DoorBird release from 0.52 to 0.54

source/_components/doorbird.markdown

@@ -0,0 +1,32 @@
+---
+layout: page
+title: "DoorBird"
+description: "Instructions on how to integrate your DoorBird video doorbell with Home Assistant."
+date: 2017-08-06 11:30
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: doorbird.png
+ha_category: Hub
+ha_release: "0.54"
+ha_iot_class: "Local Polling"
+---
+
+The `doorbird` implementation allows you to integrate your [DoorBird](http://www.doorbird.com/) device in Home Assistant.
+
+To connect your device, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+doorbird:
+  host: IP_OR_HOSTNAME
+  username: abcdef0001
+  password: xxxxxxxxxx
+```
+
+Configuration variables:
+
+- **host** (*Required*): The LAN IP address or hostname of your device. You can find this by going to the [DoorBird Online check](http://www.doorbird.com/checkonline) and entering the information from the paper that was included in the box.
+- **username** (*Required*): The username of a non-administrator user account on the device.
+- **password** (*Required*): The password for the user specified.