refactor: set DOKKU_SYSTEM_USER and DOKKU_SYSTEM_GROUP at the top-level
refactor: set DOKKU_SYSTEM_USER and DOKKU_SYSTEM_GROUP at the top-level

jimjag/dokku,alexquick/dokku,progrium/dokku,alexquick/dokku,dokku/dokku,progrium/dokku,claytonbrown/dokku,claytonbrown/dokku,dokku/dokku,claytonbrown/dokku,dokku/dokku,dokku/dokku,progrium/dokku,progrium/dokku,claytonbrown/dokku,progrium/dokku,alexquick/dokku,jimjag/dokku,alexquick/dokku,alexquick/dokku,claytonbrown/dokku,jimjag/dokku,alexquick/dokku,jimjag/dokku,alexquick/dokku,progrium/dokku,jimjag/dokku,dokku/dokku,claytonbrown/dokku,alexquick/dokku,progrium/dokku,jimjag/dokku,dokku/dokku,claytonbrown/dokku,jimjag/dokku,claytonbrown/dokku,jimjag/dokku,dokku/dokku,dokku/dokku,progrium/dokku