Understand Kotlin

https://academy.realm.io/posts/getting-started-with-kotlin-and-anko/
https://github.com/dbacinski/Android-Testing-With-Kotlin/blob/master/docs/Unit-Testing-Introduction.md
https://youtu.be/zQekzaAgIlQ
https://developer.android.com/training/basics/data-storage/shared-preferences.html 6
https://www.androidhive.info/2012/08/android-session-management-using-shared