Giving both the issue number and URL is redundent in the message.
GitLab can automatically close the issue using the URL, so only
give the URL so it can be viewed in the log.
To enable the config file run (in the root source directory):
git config --add include.path "$(pwd)/helpers/git/fixes_alias"
Then after commiting a change, you can decorate the commit with appropriate lines by:
git fixes 123456