Manage Update/Remove of hasMany field

class ManagedTeam {
    String name
    static hasMany = [ users: ManagedUser ]
}

update method in controller:

//clear all users
managedTeamInstance.users = []

//add the selected ones back
params.users.each() {
    def ManagedUser user = ManagedUser.get( it )
    managedTeamInstance.users.add( user )
    log.debug( "in associateUser: added " + user )
};

//try to save the changes
if( !managedTeamInstance.save( flush: true ) )
{
    return error()
}
else{
    flash.message = "Successfully associated users"

}