docs(*): add build steps to readme

Author: benmarten

README.md

@@ -10,6 +10,11 @@ Please refer to: https://www.leanplum.com/docs#/setup/android
 ## Development Workflow
 - We are using GitFlow branching model: https://github.com/nvie/gitflow
 - We use the Conventional Changelog Commit Style for commit messages: https://github.com/commitizen/cz-cli
+## Build the SDK
+To build the sdk run:
+```bash
+./build.sh
+```
 ## Contributing
 Please follow the Conventional Changelog Commit Style and send a pull request to `develop` branch.
 ## License