Add users to a group in CommonSense.
            
            @param parameters (dictonary) - Dictionary containing the users to add.
                                    
            @return (bool) - Boolean indicating whether GroupsPost was successful.

def GroupsUsersPost(self, parameters, group_id):
        """
            Add users to a group in CommonSense.
            
            @param parameters (dictonary) - Dictionary containing the users to add.
                                    
            @return (bool) - Boolean indicating whether GroupsPost was successful.
        """
        if self.__SenseApiCall__('/groups/{group_id}/users.json'.format(group_id = group_id), 'POST', parameters = parameters):
            return True
        else:
            self.__error__ = "api call unsuccessful"
            return False