Pull Request Requiring DB Alter

What's the best way to "bake in" a database change that is required for a pull request.

Specifically, I'm considering issuing a pull request for more secure password hashing, but it requires more than the allotted varchar(40) for the password (customer, affiliate, user) fields. Of course I can also modify the installation sql file, but that won't help people who upgrade an existing install.

Did some quick searching but couldn't find the recommended way to do this.

This should be done via migrations. bot Opencart doesn't use this.
You should modify at least `install/opencart.sql` for new installs and check `install/{controller,model}/upgrade.php`.