added README

README.md

@@ -0,0 +1,16 @@
+# TLSNotary mdBook Documentation
+
+## Build
+
+Install mdbook and mdbook-katex
+
+```bash
+cargo install mdbook --version 0.4.21
+cargo install --git "https://github.com/sinui0/mdbook-katex"
+```
+
+Then build and serve
+
+```bash
+mdbook serve
+```