Use of `basename()` for `PLUGINS_DIR` doesn't make sense

[diamondburned]

If a Kanboard installation is in a different path than its PLUGINS_DIR, e.g.

ROOT_DIR=/opt/kanboard/www
PLUGINS_DIR=/var/lib/kanboard/plugins

Then by https://github.com/creecros/Customizer/blob/master/Plugin.php#L19, basename(PLUGINS_DIR) would return plugins, and Customizer would think that the plugins directory is /opt/kanboard/www/plugins since that's the working directory.

Is there a reason why basename() is used here? Does $plugin_folder = PLUGINS_DIR work?