Add initial docs for weather component

source/_components/weather.openweathermap.markdown

@@ -0,0 +1,38 @@
+---
+layout: page
+title: "OpenWeatherMap"
+description: "Instructions how to integrate OpenWeatherMap within Home Assistant."
+date: 2016-09-29 09:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: openweathermap.png
+ha_category: Weather
+ha_release: "0.30"
+---
+
+
+The `openweathermap` weather platform uses [OpenWeatherMap](http://openweathermap.org/) as an source for current meteorological data for your location.
+
+You need an API key which is free but requires a [registration](http://home.openweathermap.org/users/sign_up).
+
+To add OpenWeatherMap to your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+weather:
+  - platform: openweathermap
+    api_key: YOUR_API_KEY
+    latitude: 46.1234
+    longitude: 7.1234
+```
+
+Configuration variables:
+
+- **api_key** (*Required*): Your API key for http://openweathermap.org/.
+- **latitude** (*Optional*): Latitude of the location to display the weather. Defaults to the latitude in your your `configuration.yaml` file. 
+- **longitude** (*Optional*): Longitude of the location to display the weather. Defaults to the longitude in your `configuration.yaml` file.
+
+Details about the API are available in the [OpenWeatherMap documentation](http://openweathermap.org/api).
+