Separate Application and Database with Firewall

[ClaireBozic]

Best practices dictate that the most secure setup for web-based applications associate with databases is to put the application outside the firewall and the database inside the firewall. This should be accommodated in the standard setup, similar to the flexibility provided to the file storage location. If not, the documentation should describe the steps to create this setup.

[seanh]

We usually set our sites up with CKAN on a frontend server, and PostgreSQL and Solr on a backend server that isn't directly exposed to the internet.

I don't think the docs should describe the exact steps to set this up, because everyone's setup will be different, but I think it would be worth adding a short "best practice" note to the docs saying that this is something people might want to consider.

I'm going to close this issue for now, but a pull request for the docs would be welcome, see http://docs.ckan.org/en/latest/contributing/documentation.html