message: docs: metion docs versions in README
diff: @@ -20,7 +20,8 @@ the option `dsn` to empty in the config file.
  ## Testnet Rylai
  -CKB Testnet *Rylai* is the testing network before its mainnet launch.
  +CKB Testnet *Rylai* is the testing network before its mainnet launch. Switch
  +to branch [rylai] to see the documentations.
  ## Mainnet
  @@ -55,6 +56,11 @@ The contribution workflow is described in [CONTRIBUTING.md](CONTRIBUTING.md), an
  [Latest version](https://github.com/nervosnetwork/ckb#documentations) is hosted in GitHub.
  +The default branch in GitHub is `develop`, if you are looking for docs for the
  +Testnet Rylai, switch to the branch [rylai].
  +
  +[rylai]: https://github.com/nervosnetwork/ckb/tree/rylai#documentations
  +
  - [Get CKB](docs/get-ckb.md)
  - [Quick Start](docs/quick-start.md)
  - [Run CKB with Docker](docs/run-ckb-with-docker.md)
  