Update README.md

contrib/README.md

@@ -1,8 +1,24 @@
+# Commands to build librocksdb
+
+## Build librocksdb.a
+
 ```bash
-docker build -t librocksdb:latest --platform=linux/amd64,linux/arm64 .
+docker build -t librocksdb:latest .
 
 docker run -it --rm -v $(pwd):/out librocksdb:latest
 
 # inside docker container
 cp /rocksdb/librocksdb.a /out
 ```
+
+## Tar librocksdb.a
+
+```bash
+tar -czvf librocksdb_8.5.3_linux_arm64.tar.gz librocksdb.a
+```
+
+## Build Mac Universal Static Library
+
+```bash
+lipo -create librocksdb_darwin_amd64.a librocksdb_darwin_arm64.a -output librocksdb.a
+```