This is a Heroku buildpack for DuckDB required to work with gem Ruby DuckDB
Add the buildpack to your Heroku app:
heroku buildpacks:add https://github.com/dataPlor/heroku-buildpack-ruby-duckdb.git
heroku config:set BUNDLE_BUILD__DUCKDB="--with-duckdb-include=/app/vendor/duckdb/include --with-duckdb-lib=/app/vendor/duckdb/lib"
it should be added before the Ruby buildpack.