Capistrano deployment, asset pipeline, ruby-debug not found - ruby-on-rails

Question

I'm deploying my Rails 3.2.2, Ruby 1.9.3 app with Capistrano to a Linux server. When I'm running a cap deploy I get this error:
* executing `deploy:assets:precompile'
* executing "cd /var/www/production/releases/20120418090209 && bundle exec rake RAILS_ENV=production RAILS_GROUPS=assets assets:precompile"
servers: ["example.com"]
[example.com] executing command
[example.com] sh -c 'cd /var/www/production/releases/20120418090209 && bundle exec rake RAILS_ENV=production RAILS_GROUPS=assets assets:precompile'
** [out :: example.com] rake aborted!
** [out :: example.com] cannot load such file -- ruby-debug
** [out :: example.com]
** [out :: example.com] (See full trace by running task with --trace)
command finished in 8962ms
*** [deploy:update_code] rolling back
* executing "rm -rf /var/www/production/releases/20120418090209; true"
servers: ["example.com"]
[example.com] executing command
[example.com] sh -c 'rm -rf /var/www/production/releases/20120418090209; true'
command finished in 176ms
failed: "sh -c 'cd /var/www/production/releases/20120418090209 && bundle exec rake RAILS_ENV=production RAILS_GROUPS=assets assets:precompile'" on example.com
It says, that the ruby-debug gem was not found. But ruby-debug is not inside the production group in my Gemfile:
group :development, :test do
gem "steak"
gem "linecache19", :git => "git://github.com/mark-moseley/linecache", :require => "ruby-debug"
gem "ruby-debug-base19x", "~> 0.11.30.pre4"
gem "ruby-debug19"
gem "rails_best_practices"
gem "ruby_parser"
gem "reek"
gem "flog"
gem "jslint_on_rails", :git => "git://github.com/psionides/jslint_on_rails"
gem "jasmine-rails"
end
Cause the error gets thrown after the rake assets:precompile command, I think it has something todo with Capistrano and the load 'deploy/assets' call inside my Capfile:
load 'deploy' if respond_to?(:namespace) # cap2 differentiator
Dir['config/deploy/recipes/*.rb','vendor/gems/*/recipes/*.rb','vendor/plugins/*/recipes/*.rb'].each { |plugin| load(plugin) }
load 'config/deploy' # remove this line to skip loading any of the default tasks
# Uncomment if you are using Rails' asset pipeline
load 'deploy/assets'
When I remove this line, everything deploys fine, but (of course) the assets aren't found in production. And, if I run bundle exec rake RAILS_ENV=production RAILS_GROUPS=assets assets:precompile directly on the server (inside the app dir) I get the same error.
So what should I do?

Answer 1

ruby-debug is obsolete. In ruby >= 1.9 you should use excellent debugger gem
see: https://github.com/cldwalker/debugger and http://railscasts.com/episodes/54-debugging-ruby-revised