Added database migration

app/src/main/java/eu/faircode/email/DB.java

@@ -68,7 +68,7 @@ import javax.mail.internet.InternetAddress;
 // https://developer.android.com/topic/libraries/architecture/room.html
 
 @Database(
-        version = 261,
+        version = 262,
         entities = {
                 EntityIdentity.class,
                 EntityAccount.class,
@@ -2644,6 +2644,11 @@ public abstract class DB extends RoomDatabase {
                         else
                             db.execSQL("UPDATE `folder` SET `hide_seen` = 0");
                     }
+                }).addMigrations(new Migration(261, 262) {
+                    @Override
+                    public void migrate(@NonNull SupportSQLiteDatabase db) {
+                        logMigration(startVersion, endVersion);
+                    }
                 }).addMigrations(new Migration(998, 999) {
                     @Override
                     public void migrate(@NonNull SupportSQLiteDatabase db) {