Add README

Author: matevz

README.md

@@ -0,0 +1,16 @@
+# Oasis API reference documentation
+
+Branch `gh-pages` in this repository hosts the https://api.docs.oasis.io
+site.
+
+## `gh-pages` organization
+
+- `js`: holds JavaScript and TypeScript packages named after the package name
+  deployed at npmjs.org, but with stripped `@oasisprotocol/` prefix. For example
+  `@oasisprotocol/client` is hosted inside `js/client` path.
+- `rust`: holds Rust packages named after the import name of the package e.g.
+  `oasis_runtime_sdk`.
+
+The branch is periodically updated by fetching the content of `api-reference`
+branch of the `oasis-sdk`, `sapphire-paratime` and other relevant Oasis
+repositories.