Update README.md

Author: LukaszLapaj

README.md

@@ -3,19 +3,24 @@
 ### AirCheck is an simple android app which combines current air pollution information from WIOŚ and Airly with very simple interface, focusing on the most important things.
 
 ## Play Store
-https://play.google.com/store/apps/details?id=com.air.check
+<a href="https://play.google.com/store/apps/details?id=com.air.check"><img src="https://play.google.com/intl/en_us/badges/images/generic/en_badge_web_generic.png" height="75"></a>
 
 ## Screenshots
 
-<img src="screenshots/1.png" width="400">
-<img src="screenshots/2.png" width="400">
+<img src="screenshots/1.png" width="410">
+<img src="screenshots/2.png" width="410">
 
 ## Build Requirements
 
 * Android Studio
 * Android Software Development Kit
 * Java Development Kit
 
-# Credits
+## Requirements
+* Android version 5.0 (Lollipop) or higher
+* GPS or up-to-date Google Play Services
+* Internet connection
+
+## Credits
 
 * WIOŚ and Airly for API