The second link in TFA for the neural network visualization leads to a heroku app 404 page. Is this a victim of Salesforce's recent policy changes taking away

The second link in TFA for the neural network visualization leads to a heroku app 404 page. Is this a victim of Salesforce's recent policy changes taking away free-tier apps? http://www.emergentmind.com/neural-network http://www.emergentmind.com/neural-network I'm hopeful it's only a typo. The level of detail and thoroughnes in this article is remarkable.