Failed to deploy to Heroku

[plaidshirtakos]

I have got following error message during deploy:

FAILURE: Build failed with an exception.
       
       * What went wrong:
       Execution failed for task ':assetCompile'.
       > A problem occurred starting process 'command 'broccoli''
       
       * Try:
       Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
       
       * Get more help at https://help.gradle.org
       
       BUILD FAILED in 1m 7s
       2 actionable tasks: 1 executed, 1 up-to-date
 !     ERROR: Failed to run Gradle!
       We're sorry this build is failing. If you can't find the issue in application
       code, please submit a ticket so we can help: https://help.heroku.com
       You can also try reverting to the previous version of the buildpack by running:
       $ heroku buildpacks:set https://github.com/heroku/heroku-buildpack-gradle#previous-version
       
       Thanks,
       Heroku
 !     Push rejected, failed to compile Gradle app.
 !     Push failed

[bianjp]

Yarn and Broccoli are required to compile frontend assets.

This is rather a simple and crude blog app which lacks many essential features, and I would not recommend anyone else to use it.