missing feed api for create new feed in group

[cyberdude86]

# Groups
def create_new_feed_in_group(self, group_key, feed_name):
    """
    Adds a new feed to a group
    :param str group_key: Group
    :param str feed_key: Feed to add to the group
    """
    path = self._compose_path("groups/{0}/feeds".format(group_key))
    payload = {"feed": {"name": feed_name}}
    return self._post(path, payload)