This class can be used to manage groups of user storing user and group records in XML files. It create a XML file with user and group information and perform several other types of operations to manipulate users and groups information, like: - Add an user group - Add an user to a group - Change the name of a group - Remove a group - Add an user - Change the password of an user - Remove an user - Verify whether a password is correct for a given user - Get the access of an user