Update the readme.

Author: fire

README.md

@@ -30,3 +30,9 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
 <!-- ALL-CONTRIBUTORS-LIST:END -->
 
 This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!
+
+## How to get build?
+
+```bash
+elixir --sname build -r buildscript.iex -e 'BuildScript.all'
+```