Method change

backend/src/git/link.rs:64–80

(
        &self,
        link: &RepoLink,
        parent_topics: &Vec<RepoTopic>,
        date: Timestamp,
    )

    }

    fn change(
        &self,
        link: &RepoLink,
        parent_topics: &Vec<RepoTopic>,
        date: Timestamp,
    ) -> activity::Change {
        let mut deleted_link = activity::LinkInfo::from(link);
        deleted_link.deleted = true;

        activity::Change::DeleteLink(activity::DeleteLink {
            actor_id: self.actor.user_id.to_owned(),
            date,
            deleted_link,
            id: activity::Change::new_id(),
            parent_topics: activity::TopicInfoList::from(parent_topics),
        })
    }
}

pub struct UpdateLinkParentTopics {