--------- beginning of crash
2020-05-01 12:30:41.839 25753-25957/org.mozilla.fenix.debug E/AndroidRuntime: FATAL EXCEPTION: arch_disk_io_1
    Process: org.mozilla.fenix.debug, PID: 25753
    java.lang.RuntimeException: Exception while computing database live data.
        at androidx.room.RoomTrackingLiveData$1.run(RoomTrackingLiveData.java:92)
        at androidx.room.TransactionExecutor$1.run(TransactionExecutor.java:45)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:919)
     Caused by: java.lang.IllegalStateException: A migration from 3 to 2 was required but not found. Please provide the necessary Migration path via RoomDatabase.Builder.addMigration(Migration ...) or allow for destructive migrations via one of the RoomDatabase.Builder.fallbackToDestructiveMigration* methods.
        at androidx.room.RoomOpenHelper.onUpgrade(RoomOpenHelper.java:101)
        at androidx.room.RoomOpenHelper.onDowngrade(RoomOpenHelper.java:113)
        at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper$OpenHelper.onDowngrade(FrameworkSQLiteOpenHelper.java:135)
        at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:415)
        at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:317)
        at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper$OpenHelper.getWritableSupportDatabase(FrameworkSQLiteOpenHelper.java:92)
        at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper.getWritableDatabase(FrameworkSQLiteOpenHelper.java:53)
        at androidx.room.RoomDatabase.beginTransaction(RoomDatabase.java:328)
        at mozilla.components.feature.top.sites.db.TopSiteDao_Impl$3.call(TopSiteDao_Impl.java:113)
        at mozilla.components.feature.top.sites.db.TopSiteDao_Impl$3.call(TopSiteDao_Impl.java:110)
        at androidx.room.RoomTrackingLiveData$1.run(RoomTrackingLiveData.java:90)
        at androidx.room.TransactionExecutor$1.run(TransactionExecutor.java:45) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
        at java.lang.Thread.run(Thread.java:919)