>Need a production solr instance? The Heroku way is to use a 3rd party add-on such as websolr. This means creating yet another account to keep track of, adding another bill to your credit card statement, dealing with one more mediocre web interface, and creating an even larger divide between your development and production environments.

Nothing prevents you to use your own solr(or any other server) of your own inside your application deployed in heroku if you want