Run custom commands during the build process.
heroku buildpacks:add --index 1 https://github.com/pinguet62/heroku-buildpack-exec
echo 'web: npm start -- --environment prod --port $PORT' > Procfile
-----> Exec buildpack app detected -----> "EXEC_CMD" environment variable found Executing "EXEC_CMD" command... <command_logs>
command_logs is the output logs generated by the command.
In practice, this buildpack execute
eval "$EXEC_CMD" command.
Copy the snippet above into CLI.