There are a few utility commands for ranks, so you don't have to do everything in the configs.
/ranks add <name> [parent]- Creates a new rank with optional parent
/ranks delete|del <rank>- Deletes a rank
/ranks set <player> <rank|none>- Sets or removes player's rank
/ranks get [player]- Prints player's rank
/ranks get_permission|getp <player> <permission>- Prints permission value for the specified player
/ranks set_permission|setp <rank> <permission> <value|none>- Sets permission for rank