I am suing Heroku dev plan for creating database using PostgreSQL. Database is created in Heroku. After running heroku pg:info command
$ heroku
If you have multiple applications on a heroku server, you can do:
heroku run bash -a application-name
this will open a bash container for that specific application, and you can run any command inside this container. i.e
php artisan migrate:refresh --seed
Obviously you'll first need to make sure that you are already logged in to the heroku cli.