Save the taskfile in the config

        :param tfi: the last selected taskfileinfo
        :type tfi: class:`jukeboxcore.filesys.TaskFileInfo`
        :returns: None
        :rtype: None
        :raises: None

def save_lastfile(self, tfi):
        """Save the taskfile in the config

        :param tfi: the last selected taskfileinfo
        :type tfi: class:`jukeboxcore.filesys.TaskFileInfo`
        :returns: None
        :rtype: None
        :raises: None
        """
        tf = models.TaskFile.objects.get(task=tfi.task, version=tfi.version, releasetype=tfi.releasetype,
                                         descriptor=tfi.descriptor, typ=tfi.typ)
        c = self.get_config()
        c['lastfile'] = tf.pk
        c.write()