Upgrading from version 2.0.9 to 2.2.0

1. backup your datasets. Always a good idea!

2. install SQL-Ledger over top of your old installation
   $ cd /usr/local
   $ tar zxvf sql-ledger-2.2.0.tar.gz

3. copy Default-pos_invoice.txt to
   templates/your_private_directory/pos_invoice.txt
   and edit to suit.

