Unable to access previewer because of default server name being localhost

[sgharms]

I do all my work on my Digital Ocean droplet (so pure CLI-land).

I write a post and the preview server allows me to point link (text-based browser) to 3400 and see my in-development post (yay).

But what if I want my remote machine (i.e. a laptop) to see that same server? To the best of my debugging, the rack server starts up serving while bound to localhost. If I adjust the rackup command, for the :preview task to include a -o to mydomain.com I'm able to access from a full browser.

As such, the feature request would be to add support for a hostname to the Rakefile. I believe this option could be defined elsewhere (in the config.ru), but adding the option in Rakefile keeps the configuration parameter in the same abstraction as server_port, so that seems consistent.
#1744 changes the code to work in the base-case. Changing the value of server_host to mydomain.com has me working both locally and remotely.