`article.url` does not include port number

Just as the title says, calling `article.url` includes the path, the domain, the protocol, but not the port.

Run rackup locally, and open your atom feed. (Presuming rack uses a non-standard port) If you look at the ID (that should be fixed, but w/e) or link, the port is not shown.

Reproduce the issue by running rackup locally on a non-standard port and opening the Atom feed. Trace how article.url produces the feed link and ID; done when the generated link includes the port number.

Written by the indexing model from the issue text.