Add readme.

readme.md

@@ -0,0 +1,27 @@
+# Czech Republic Air Quality Measurements
+
+This custom component provides a air quality measurements provides by Czech Hydro-meteorological Institute [CHMU](http://www.chmi.cz/?tab=2/). 
+
+Multiple air quality stations may be configured.
+
+## Installation
+
+### Using [HACS](https://hacs.xyz/)
+
+[![Open your Home Assistant instance and open a repository inside the Home Assistant Community Store.](https://my.home-assistant.io/badges/hacs_repository.svg)](https://my.home-assistant.io/redirect/hacs_repository/?owner=dvejsada&repository=Air_Quality_CZ&category=Integration)
+
+### Manual
+
+To install this integration manually you have to download cz_air_quality folder into your config/custom_components folder.
+
+## Configuration
+
+### Using UI
+
+From the Home Assistant front page go to **Configuration** and then select **Integrations** from the list.
+
+Use the "plus" button in the bottom right to add a new integration called **CHMU Air Quality** and choose preferred air quality station.
+
+You can find the closest air quality station [here](http://pr-asu.chmi.cz:8080/IskoOzarkApp/rest/map_3h_cz/
+
+The success dialog will appear or an error will be displayed in the popup. Please note that not all stations measure all pollutants - some entities thus may be unavailable.