Add binary rest sensor docs

source/_components/binary_sensor.rest.markdown

@@ -0,0 +1,52 @@
+---
+layout: component
+title: "RESTful binary sensor"
+description: "Instructions how to integrate REST binary sensors into Home Assistant."
+date: 2015-12-17 19:10
+sidebar: true
+comments: false
+sharing: true
+footer: true
+ha_category: Binary Sensor
+---
+
+
+The `rest` binary sensor platform is consuming a given endpoint which is exposed by a [RESTful API](https://en.wikipedia.org/wiki/Representational_state_transfer) of a device, an application, or a web service. The binary sensor has support for GET and POST requests.
+
+To enable this sensor, add the following lines to your `configuration.yaml` file for a GET request:
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  platform: rest
+  resource: http://IP_ADDRESS/ENDPOINT
+  method: GET
+  name: REST GET binary sensor
+  value_template: '{% raw %}{{ value_json.state }}{% endraw %}'
+```
+
+or for a POST request:
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  platform: rest
+  resource: http://IP_ADDRESS/ENDPOINT
+  method: POST
+  value_template: '{% raw %}{{ value_json.state }}{% endraw %}'
+  payload: '{ "device" : "door" }'
+  name: REST POST binary sensor
+```
+
+Configuration variables:
+
+- **resource** (*Required*): The resource or endpoint that contains the value.
+- **method** (*Optional*): The method of the request. Default is GET.
+- **value_template** (*Optional*): Defines a [template](/getting-started/templating/) to extract the value.
+- **payload** (*Optional*): The payload to send with a POST request. Usualy formed as a dictionary.
+- **name** (*Optional*): Name of the REST binary sensor.
+
+<p class='note warning'>
+Make sure that the URL matches exactly your endpoint or resource.
+</p>
+