Add prefix for asset urls

[Falco]

Read the docs, Luke:

Use a subfolder (path prefix) to serve Discourse with multiple servers sharing a domain

Let’s say you have a WordPress blog on http://=DOMAIN=, and you want to serve your Discourse forums (which run on a different server) from http://=DOMAIN==PATH=. How do you do that? Note: This won’t work for serving multiple Discourse instances from different folders on the same domain. You need to use different subdomains so that each site can have different cookies. You’re going to need to send all traffic for the domain to one place that can route traffic to the correct server. In thi…