Gorm Custom ORM mapping one-to-many relationship foreign key

We have an existing mysql db I am trying to map into Grails domain. An appointment has many appointment histories, and is mapped to appointment_history by compentity_id column in db table. I am trying to define one-to-many relationship in Grails, but it creates an apponitment_id column in appointment_history table. Here is how the domains look like:

class Appointment {

Date created
Date updated
String status

String title
Date startDate
Date endDate
Integer customerId
Integer createdUserId
String itemType
Integer opportunityId
String note
String timeZone

static hasMany = [histories: AppointmentHistory, notes: AppointmentNotes, ibUsers : ImplantBaseUser]
static belongsTo = [ImplantBaseUser]

static constraints = {
}

static mapping = {
histories column:'compentity_id'
note type: 'text'
}
}


class AppointmentHistory {
Date created
Integer userId
String userName
String action
String description


static belongsTo = [appointment: Appointment]

static constraints = {
}

static mapping = {
description type: 'text'
}
}

And tables:

CREATE TABLE `appointment` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`created` datetime DEFAULT NULL,
`updated` datetime DEFAULT NULL,
`status` varchar(25) DEFAULT NULL,
`published` datetime DEFAULT NULL,
`activated` datetime DEFAULT NULL,
`title` varchar(255) DEFAULT NULL,
`start_date` datetime DEFAULT NULL,
`end_date` datetime DEFAULT NULL,
`notes` text,
`customer_id` int(11) DEFAULT NULL,
`created_user_id` int(11) DEFAULT NULL,
`item_type` varchar(255) DEFAULT NULL,
`opportunity_id` int(11) DEFAULT NULL,
`note` text,
`time_zone` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
)

CREATE TABLE `appointment_history` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`created` datetime DEFAULT NULL,
`compentity_id` int(11) DEFAULT '0',
`user_id` int(11) DEFAULT '0',
`user_name` varchar(255) DEFAULT NULL,
`action` varchar(25) DEFAULT NULL,
`description` text,
PRIMARY KEY (`id`),
KEY `appointment_history_i_compentity_id` (`compentity_id`)
)

What am I missing here? All I am trying to do, is, ask Grails to use compentity_id as foreign key (= appointment.id) and not generate an appointment_id column in appointment_history table..any idea?