Added documentation for updater component

source/_components/updater.markdown

@@ -0,0 +1,30 @@
+---
+layout: component
+title: "Updater"
+description: "Detecting when Home Assistant updates are available."
+date: 2015-11-15 20:40
+sidebar: true
+comments: false
+sharing: true
+footer: true
+ha_category: Other
+---
+
+The updater component will detect when the newest published version of Home
+Assistant does not match the currently installed version. When running,
+it will check for new releases at startup and everyday at noon and midnight.
+
+For an added bonus, an automation component can be created to send a message
+with a notifier when that state of this component's entity changes.
+
+``` yaml
+automation:
+  alias: 'Update Available Notifications'
+  trigger:
+    platform: state
+    entity_id: updater.updater
+  action:
+    service: notify.notify
+    data:
+      message: 'Home Assistant update is available.'
+```