Add Random binary sensor docs (#3798)

source/_components/binary_sensor.random.markdown

@@ -0,0 +1,35 @@
+---
+layout: page
+title: "Random Binary Sensor"
+description: "Instructions how to integrate random state sensors into Home Assistant."
+date: 2017-10-27 08:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: home-assistant.png
+ha_category: Sensor
+ha_iot_class: "Local Polling"
+ha_release: 0.57
+---
+
+
+The `random` binary sensor platform is creating random states (`True`, 1, `on` or `False`, 0, `off`). This can be useful if you want to test automation rules. It generates a new state every time it is polled.
+
+To enable the random binary sensor, add the following lines to your `configuration.yaml`:
+
+```yaml
+# Example configuration.yaml entry
+binary_sensor:
+  - platform: random
+```
+
+{% configuration %}
+  name:
+    description: Name to use in the frontend.
+    required: false
+    type: string
+{% endconfiguration %}
+
+See the [entity component options](/docs/configuration/platform_options/) to control how often the main component polls the random binary sensor. The default is 30 seconds.
+