Update readme.

README.md

-#
+#Vereign mobile application.
 
-Vereign mobile application.
+## Application flavors
+- Debug with `development` flavor `flutter run --flavor development -t lib/main-dev.dart`
+- Debug with `production` flavor `flutter run --flavor production -t lib/main.dart`
 
-## Getting Started
+
+## Flutter Getting Started
 
 This project is a starting point for a Flutter application.