docs: 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)