spotify media player documentation (#2406)

* spotify media player documentation

* update spotify doc

source/_components/media_player.spotify.markdown

@@ -0,0 +1,51 @@
+---
+layout: page
+title: "Spotify"
+description: "Instructions on how to integrate Spotify into Home Assistant."
+date: 2017-04-10 08:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: spotify.png
+ha_category: Media Player
+featured: false
+ha_release: 0.43
+ha_iot_class: "Cloud Polling"
+---
+
+The `spotify` media player platform allows you to control [Spotify](https://www.spotify.com/) playback from Home Assistant.
+
+## {% linkable_title Prerequisites %}
+
+- Spotify Premium account.
+- Spotify Application, properly configured.
+
+To create the required Spotify Application, login to [Spotify Developer](https://developer.spotify.com), visit the [My Applications](https://developer.spotify.com/my-applications/#!/applications) page, and select **Create An App**. Enter any name and description. Once your application is created, you can view it and discover your **Client ID** and **Client Secret**, which are placed in the Home Assistant configuration file. Finally, add a **Redirect URI** in the following form:
+
+`http://<your_home_assistant_url_or_local_ip>/api/spotify`
+
+Remember to select **Save** after adding the URI.
+
+
+## {% linkable_title Configuration %}
+
+To add Spotify to your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+media_player:
+  - platform: spotify
+    client_id: <your client id>
+    client_secret: <your client secret>
+```
+
+Configuration variables:
+
+- **client_id** (*Required*): Client ID from your Spotify Application.
+- **client_secret** (*Required*): Client Secret from your Spotify Application.
+- **cache_path** (*Optional*): Path to cache authentication token (defaults to configuration directory).
+
+## {% linkable_title Setup %}
+
+After the prerequisites and configuration are complete, restart Home Assistant. A **Spotify** configurator element will be available. Follow the instructions to authorize Home Assistant to access your Spotify account. A Spotify media player will then appear.