[SL] System for updating user copies of sql-ledger and retaining user fiddles

[Bob G. <bo...@rc...>]

If you have been tempted to make changes to the sql-ledger code to
respond to local requirements, using svn as your source code control
system offers an 'easy' way to handle your changes and the upgrade to
new versions when they come out.

This piece of the svn handbook outlines the approach:

http://svnbook.red-bean.com/nightly/en/svn.advanced.vendorbr.html