Make sure to fill in the App name (1) field with something unique, and then fill the DOMAIN (2) variable with the external domain you wish your Squidex instance to be available on.
You can ignore MONGO_USERNAME and MONGO_PASSWORD for now.
When you are done, click Deploy App.
When it's finished, click Manage app (1).
On the Dashboard, click ObjectRocket for MongoDB (1).
On the ObjectRocket Dashboard, click DATABASES (1) and then Add Database (2).
Enter the database name (1) (must be
squidex), the username and the password (2). Keep note of those, as you will be needing them for the next step.
Back at the Heroku Dashboard, click Settings (1), then click Reveal Config Vars (2).
Fill the fields
MONGO_PASSWORD (1) and
MONGO_USERNAME (2) with the same credentials you provided in the previous step.
You should then be ready to go!
Please check the logs by clicking More, and then View logs.
In case the deployment gets stuck, go to the top right of the dashboard, click More and then Restart all dynos.
It is very likely a configuration problem and not related to hosting under Docker. Checkout