added readme file with app screenshots

README.md

@@ -0,0 +1,17 @@
+# Spacetime
+
+Simple but awesome stopwatch timer app with cool [nasa](https://github.com/sirekanian/apod) wallpapers
+
+<picture>
+  <img width="200" src="app/src/main/play/listings/en-US/graphics/phone-screenshots/1.png">
+</picture>
+
+<picture>
+  <img width="200" src="app/src/main/play/listings/en-US/graphics/phone-screenshots/2.png">
+</picture>
+
+<picture>
+  <img width="200" src="app/src/main/play/listings/en-US/graphics/phone-screenshots/3.png">
+</picture>
+
+<a href='https://play.google.com/store/apps/details?id=com.sirekanian.spacetime'><img height='100' alt='Get it on Google Play' src='https://play.google.com/intl/en_us/badges/images/generic/en_badge_web_generic.png'/></a>