This is my first time trying to set up capistrano to deploy a rails application. I am deploying from my local machine to my remote server that has the repo, web, app, and mysql servers all on the same machine. I am following this walk through: http://www.capify.org/index.php/From_The_Beginning

I get to the command

cap deploy:start

Then I get this error:

*** [err :: example.com] sudo: unknown user: app
   command finished
failed: "sh -c 'cd /var/www/example/current && sudo -p '\\''sudo password: '\\'' -u app nohup script/spin'" on example.com

Am I supposed to add an 'app' user, or is there a way of changing what user the command runs as?

This is my deploy.rb:

set :application, "example"
set :repository,  "[email protected]:example.git"
set :user, "trobrock"
set :branch, 'master'

set :deploy_to, "/var/www/example"

set :scm, :git
# Or: `accurev`, `bzr`, `cvs`, `darcs`, `git`, `mercurial`, `perforce`, `subversion` or `none`

role :web, "example.com"                           # Your HTTP server, Apache/etc
role :app, "example.com"                           # This may be the same as your `Web` server
role :db,  "example.com", :primary => true         # This is where Rails migrations will run

And obviously everywhere it says example.com is my servers hostname and every it just says example is the app name.