add toc for week 3

Signed-off-by: Alex Chi <iskyzh@gmail.com>

mini-lsm-book/src/SUMMARY.md

@@ -13,7 +13,7 @@
   - [Write Path](./week1-06-write-path.md)
   - [Snack Time: SST Optimizations](./week1-07-sst-optimizations.md)
 
-- [Week 2 Overview: Compaction and Persistence](./week2-overview.md)
+- [Week 2 Overview: Compaction + Persistence](./week2-overview.md)
   - [Compaction Implementation](./week2-01-compaction.md)
   - [Simple Compaction Strategy](./week2-02-simple.md)
   - [Tiered Compaction Strategy](./week2-03-tiered.md)
@@ -23,6 +23,13 @@
   - [Snack Time: Batch Write and Checksums (WIP)](./week2-07-snacks.md)
 
 - [Week 3 Overview: MVCC (WIP)](./week3-overview.md)
+  - [Timestamp Encoding + Refactor](./week3-01-ts-key-refactor.md)
+  - [Snapshots - Memtables and SSTs](./week3-02-snapshot-read-part-1.md)
+  - [Snapshots - Engine Read Path](./week3-03-snapshot-read-part-2.md)
+  - [Watermark and GC](./week3-04-watermark.md)
+  - [Transaction and OCC](./week3-05-txn-occ.md)
+  - [Serializable Snapshot Isolation](./week3-06-serializable.md)
+  - [Snack Time: Compaction Filter](./week3-07-compaction-filter.md)
 - [The Rest of Your Life (TBD)](./week4-overview.md)
 
 ---

mini-lsm-book/src/week3-01-ts-key-refactor.md

@@ -0,0 +1 @@
+# Timestamp Key Encoding + Refactor

mini-lsm-book/src/week3-02-snapshot-read-part-1.md

@@ -0,0 +1 @@
+# Snapshot Read - Memtables and SSTs

mini-lsm-book/src/week3-03-snapshot-read-part-2.md

@@ -0,0 +1 @@
+# Snapshot Read - Engine Read Path

mini-lsm-book/src/week3-04-watermark.md

@@ -0,0 +1 @@
+# Watermark and Garbage Collection

mini-lsm-book/src/week3-05-txn-occ.md

@@ -0,0 +1 @@
+# Transaction and Optimistic Concurrency Control

mini-lsm-book/src/week3-06-serializable.md

@@ -0,0 +1 @@
+# Serializable Snapshot Isolation

mini-lsm-book/src/week3-07-compaction-filter.md

@@ -0,0 +1 @@
+# Snack Time: Compaction Filter