Add tagging convention in README

Author: mssun

README.md

@@ -1,10 +1,22 @@
-## Current Branch
+## Branch
 
-- `master`: Teaclave SGX SDK 1.1.0 and Intel SGX SDK 2.7.1
+- `master`/`sgx1.1.0`: Teaclave SGX SDK 1.1.0 (Intel SGX SDK 2.7.1)
 
 ## Version
 
 Given a version number X.Y.Z, increment:
 - X when making incompatible structural/API changes
 - Y when updating Teaclave SGX SDK
 - Z when adding, updating, deprecating and deleting crates
+
+For example:
+
+- crates-sgx 0.1.0: Teaclave SGX SDK 1.1.0 (Intel SGX SDK 2.7.1) + 10 SGX crates
+- crates-sgx 0.1.1: Teaclave SGX SDK 1.1.0 (Intel SGX SDK 2.7.1) + 20 SGX crates
+- crates-sgx 0.2.0: Teaclave SGX SDK 1.2.0 (Intel SGX SDK 2.8) + 20 SGX crates
+
+## Tag
+
+Tag follows this convention `v{x.y.z}+sgx{x.y.z}`, where:
+- `v{x.y.z}` is the version of crates-sgx
+- `sgx{x.y.z}` is the version of Teaclave SGX SDK