Trying to install danbooru - Rails/Ruby asking for “@localhost” password on deploy:setup

Howdy, I'm trying to install the "danbooru" software to have it publicly available as a site. I'm pretty new but have learned pretty quick so far, but I'm at a dead end.

This is what I'm trying to get up and running: https://github.com/r888888888/danbooru

I've made it to the deployment step, however it prompts me to login to a nameless user @localhost (i.imgur.com/ONp69.png)

   danbooru@teemo:~/danbooru$ bundle exec cap development deploy:setup
 [9951bc77] Running /usr/bin/env [ -d ~/.rbenv/versions/2.1.5 ] on localhost
 [9951bc77] Command: [ -d ~/.rbenv/versions/2.1.5 ]
@localhost's password:
@localhost's password:
@localhost's password:
(Backtrace restricted to imported tasks)
cap aborted!
SSHKit::Runner::ExecuteError: Exception while executing on host localhost: Authentication failed for user @localhost
Net::SSH::AuthenticationFailed: Authentication failed for user @localhost
Tasks: TOP => rbenv:validate
(See full trace by running task with --trace)

I posted about this previously on stackoverflow, and was told that:

"You can see on Github that the production and staging deployment configuration includes a :user setting, but that's not defined in the development config. The development environment is normally used by programmers making changes to the code; if you're trying to deploy the site so it's publicly available, then you should edit your copy of the production configuration to refer to a user account & server you have access to."

so I added set :user, "albert"
and then… this messy mess happened: i.imgur.com/UHsA0Ys.png

I'm not sure I added the user properly, but I'm also not entirely sure if that's the problem to begin with. I've been able to google around and learn things myself up until this point. Any help would be greatly appreciated, but I'll continue trying to figure it out and post back if I figure out anything.