Git changelog hook

This hook should be used as prepare-commit-msg. It uses the staged diff of a pre-determined "changelog" file to pre-fill the commit message.

For example, if you add this in your changelog file prior to committing:

- Fix #1234: prevent crash when arguments missing

the hook will take this out of the diff to be committed and pre-fill the commit message with :

Fix #1234: prevent crash when arguments missing

The file to check is determined by the hooks.changelogfile config setting, and defaults to CHANGES.

This hook is copyright 2015 by Georg Brandl, and can be distributed under the GNU GPL version 2 or later.