Add given user to a group

        :param username: str
        :param group_name: str
        :return: Current state of the group

def add_user_to_group(self, username, group_name):
        """
        Add given user to a group

        :param username: str
        :param group_name: str
        :return: Current state of the group
        """
        url = 'rest/api/2/group/user'
        params = {'groupname': group_name}
        data = {'name': username}

        return self.post(url, params=params, data=data)