add contents for mdbook

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

mini-lsm-book/src/SUMMARY.md

@@ -1,3 +1,15 @@
-# Summary
+# LSM in a Week
 
-- [Chapter 1](./chapter_1.md)
+[Overview](./00-overview.md)
+
+---
+
+- [Store key-value pairs in little blocks](./01-block.md)
+- [And make them into an SST](./02-sst.md)
+- [Now it's time for a storage engine](./03-engine.md)
+- [Block cache, the good way](./04-block-cache.md)
+- [Let's do something in the background](./05-compaction.md)
+- [Be careful when the system crashes](./06-recovery.md)
+- [A good bloom filter makes life easier](./07-bloom-filter.md)
+- [Save some space, hopefully](./08-key-compression.md)
+- [What's next](./09-whats-next.md)