get a reference to the db after app launch to make sure it gets created in time

app/src/main/kotlin/com/simplemobiletools/calendar/activities/MainActivity.kt

@@ -68,6 +68,10 @@ class MainActivity : SimpleActivity(), RefreshRecyclerViewListener {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
         appLaunched()
+
+        // just get a reference to the database to make sure it is created properly
+        dbHelper
+
         checkWhatsNewDialog()
         calendar_fab.beVisibleIf(config.storedView != YEARLY_VIEW)
         calendar_fab.setOnClickListener {