Create a forked from/to relation between existing projects.

        Args:
            forked_from_id (int): The ID of the project that was forked from
            **kwargs: Extra options to send to the server (e.g. sudo)

        Raises:
            GitlabAuthenticationError: If authentication is not correct
            GitlabCreateError: If the relation could not be created

def create_fork_relation(self, forked_from_id, **kwargs):
        """Create a forked from/to relation between existing projects.

        Args:
            forked_from_id (int): The ID of the project that was forked from
            **kwargs: Extra options to send to the server (e.g. sudo)

        Raises:
            GitlabAuthenticationError: If authentication is not correct
            GitlabCreateError: If the relation could not be created
        """
        path = '/projects/%s/fork/%s' % (self.get_id(), forked_from_id)
        self.manager.gitlab.http_post(path, **kwargs)