Add initial docs for KNX cover (#2845)

source/_components/cover.knx.markdown

@@ -0,0 +1,34 @@
+---
+layout: page
+title: "KNX Cover"
+description: "Instructions on how to integrate KXN covers with Home Assistant."
+date: 2017-06-18 12:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: knx.png
+ha_category: DIY
+ha_release: 0.48
+ha_iot_class: "Local Polling"
+---
+
+
+The `knx` cover platform is used as in interface with KNX covers.
+
+To use your KNX covers in your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+cover:
+  - platform: knx
+    updown_address: 9/0/0
+    stop_address: 9/0/1
+```
+
+- **updown_address** (*Required*): The KNX group address that is used to move the cover up and down.
+- **stop_address** (*Required*): The group address that is used to stop the cover.
+- **setposition_address** (*Optional*): The group address that is used to set the position.
+- **getposition_address** (*Optional*): The group address that is used to read the position.
+- **name** (*Optional*): A name for this devices used within Home Assistant.
+