compareToIgnoreCase Hi.
The plugin.yml should use locale as a section instead of a prefix.
So instead of locale_prefix you'd use
locale:
prefix: '&7[&cRegister&7]'
[ • • • ]
The same goes for help_. You'll be able to get the config files via locale.prefix instead of locale_prefix. ?
You may want to also group the database settings as
database:
host: ***
EDIT: You may also want to add a /register reload command that reloads the config from config.yml so the user doesn't have to restart the server, as it can take from 5 seconds to a few minutes, depending on the plugins the server has and how resource intensive they are.