diff --git a/dump.rdb b/dump.rdb
new file mode 100644
index 0000000000..c324d203be
Binary files /dev/null and b/dump.rdb differ
diff --git a/src/topics/bookmarks.ts b/src/topics/bookmarks.ts
new file mode 100644
index 0000000000..58c4fb67f2
--- /dev/null
+++ b/src/topics/bookmarks.ts
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+'use strict';
+
+import async from 'async';
+import db from '../database';
+import user from '../user';
+
+export function bookmarks(Topics: any) {
+	Topics.getUserBookmark = async function (tid: [number], uid: number) {
+		if (parseInt(uid.toString(), 10) <= 0) {
+			return null;
+		}
+		return await db.sortedSetScore(`tid:${tid}:bookmarks`, uid);
+	};
+
+	Topics.getUserBookmarks = async function (tids: [number], uid: number) {
+		if (parseInt(uid.toString(), 10) <= 0) {
+			return tids.map(() => null);
+		}
+		return await db.sortedSetsScore(tids.map(tid => `tid:${tid}:bookmarks`), uid);
+	};
+
+	Topics.setUserBookmark = async function (tid: [number], uid: number, index: any) {
+		if (parseInt(uid.toString(), 10) <= 0) {
+			return;
+		}
+		await db.sortedSetAdd(`tid:${tid}:bookmarks`, index, uid);
+	};
+
+	Topics.getTopicBookmarks = async function (tid: [number]) {
+		return await db.getSortedSetRangeWithScores(`tid:${tid}:bookmarks`, 0, -1);
+	};
+
+	Topics.updateTopicBookmarks = async function (tid: number , pids: string) {
+		const maxIndex = await Topics.getPostCount(tid);
+		const indices = await db.sortedSetRanks(`tid:${tid}:posts`, pids);
+		const postIndices = indices.map(i => (i === null ? 0 : i + 1));
+		const minIndex = Math.min(...postIndices);
+
+		const bookmarks = await Topics.getTopicBookmarks(tid);
+
+		const uidData = bookmarks.map(b => ({ uid: b.value, bookmark: parseInt(b.score, 10) }))
+			.filter(data => data.bookmark >= minIndex);
+
+		await async.eachLimit(uidData, 50, async (data) => {
+			let bookmark = Math.min(data.bookmark, maxIndex);
+
+			postIndices.forEach((i) => {
+				if (i < data.bookmark) {
+					bookmark -= 1;
+				}
+			});
+
+			// make sure the bookmark is valid if we removed the last post
+			bookmark = Math.min(bookmark, maxIndex - pids.length);
+			if (bookmark === data.bookmark) {
+				return;
+			}
+
+			const settings = await user.getSettings(data.uid);
+			if (settings.topicPostSort === 'most_votes') {
+				return;
+			}
+
+			await Topics.setUserBookmark(tid, data.uid, bookmark);
+		});
+	};
+};
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000000..03a6e64df4
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,8 @@
+{
+    "compilerOptions": {
+      "outDir": "./built",
+      "allowJs": true,
+      "target": "es2017"
+    },
+    "include": ["./src/**/*"]
+  }
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