Previous version didn't include the postgresql.sql file, because of the exclude rule. Also, as the dump is now included, we exclude the contents of the postgres container.
* Add litecoin datadir to exclude
If you are running a litecoin node, litecoin datadir does not need to be included. It is only exclude, so no error in case of pure bitcoin install.
* Add huge fat warning to the backup script
If someone is looking around and trying to find a good backup solution, make sure they know the limitations
