Optional config for roundcube

[freman]

Hey, so at the moment the only way to tweak roundcube config (say to add config for a plugin) is to replace a config file, I'd like to propose the following change

mkdir config/config.inc.d/
mv config/config.docker.inc.php config/config.inc.d/

replace the include line from config.inc.d to

foreach (glob("config.inc.d/*.php") as $filename)
{
    include $filename;
}

We could mount various configs into that dir.

alternatively just have config.docker.inc.php check for a user include mounted into that dir and include that...