Cap deploy issue

deploy.rb

require "bundler/capistrano"
require 'rvm/capistrano'

set :rvm_ruby_string, '2.0.0'
set :rvm_type, :system

set :application,     "demo"
set :server_address,  "rackspace"
set :use_sudo,        false
set :use_monit,       false
set :domain,          "cybrains.net"
set :user,            "deploy"
set :group,           "deploy"
set :rails_env,       "production"

# shared paths
set :site_path,           "/home/deploy/sites/n2b"
set :deploy_to,           "#{site_path}/application/#{application}"
set :shared_config_path,  "#{shared_path}/config"

# Configuration
set :scm,         :git
set :repository,  "git@rackspace.cybrains.net:n2b-demo.git"

# allow local keys instead of server's keys
# SEE: https://help.github.com/articles/using-ssh-agent-forwarding
# allow git password prompts (not needed with forward_agent "true")
ssh_options[:forward_agent] = true
default_run_options[:pty] = false

set :deploy_via, :remote_cache

# Servers
role :app,  server_address
role :web,  server_address
role :db,   server_address, :primary => true

before "deploy:assets:precompile", "deploy:copy_configs"
before "bundle:install", "deploy:ruby_version"

# Overrides
namespace :deploy do
  desc "copies the saved config files"
  task :copy_configs, :roles => :app do 
    # Copy config files to latest release
    run "cp #{shared_config_path}/* #{release_path}/config/"
  end
end

##################################
### Passenger Deploy Overrides ###
##################################

namespace :deploy do
  desc "show ruby version"
  task :ruby_version do 
    puts '*' * 40
    puts capture("ruby --version").strip
    puts '*' * 40
  end
  
  desc "Restarting mod_rails with restart.txt"
  task :restart, :roles => :app, :except => { :no_release => true } do
    run "#{try_sudo} touch #{File.join(current_path,'tmp','restart.txt')}"
  end
 
  [:start, :stop].each do |t|
    desc "#{t} task is a no-op with mod_rails"
    task t, :roles => :app do ; end
  end
end

##################################
###  MySQL automatic backups   ###
##################################

set :backup_db_path, "#{shared_path}/backups"

def remote_file_exists?(full_path)
  'true' ==  capture("if [ -e #{full_path} ]; then echo 'true'; fi").strip
end

namespace :db do
  desc 'Backup database before deploy'
  task :backup, :roles => :db, :only => {:primary => true} do
    run "mkdir -p #{backup_db_path}" # Create a backup folder unless exists
 
    # Check if we've got database config
    if remote_file_exists?("#{current_path}/config/database.yml")    
      text = capture("cat #{current_path}/config/database.yml")
      config = YAML::load(text)[rails_env]
 
      filename = "#{backup_db_path}/#{config['database']}_#{Time.now.strftime("%m%d%Y%H%I%S")}.sql.gz"

      run "mysqldump -u #{config['username']} -p #{config['database']} | gzip --best > #{filename}" do |ch, stream, out|
        ch.send_data "#{config['password']}\n" if out =~ /^Enter password:/
      end
    else
      logger.debug("[Backup] No configuration file was found.")
    end
  end
end

stdout

09:38:32:demo >> cap deploy
    triggering load callbacks
  * 2013-08-16 09:38:41 executing `deploy'
  * 2013-08-16 09:38:41 executing `deploy:update'
 ** transaction: start
  * 2013-08-16 09:38:41 executing `deploy:update_code'
    updating the cached checkout on all servers
    executing locally: "git ls-remote git@rackspace.cybrains.net:n2b-demo.git HEAD"
    command finished in 1795ms
  * executing "if [ -d /home/deploy/sites/n2b/application/demo/shared/cached-copy ]; then cd /home/deploy/sites/n2b/application/demo/shared/cached-copy && git fetch -q origin && git fetch --tags -q origin && git reset -q --hard b48fd42788eb54a7deb02d70c760573e949bc04d && git clean -q -d -x -f; else git clone -q git@rackspace.cybrains.net:n2b-demo.git /home/deploy/sites/n2b/application/demo/shared/cached-copy && cd /home/deploy/sites/n2b/application/demo/shared/cached-copy && git checkout -q -b deploy b48fd42788eb54a7deb02d70c760573e949bc04d; fi"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 4488ms
    copying the cached version to /home/deploy/sites/n2b/application/demo/releases/20130816133848
  * executing "cp -RPp /home/deploy/sites/n2b/application/demo/shared/cached-copy /home/deploy/sites/n2b/application/demo/releases/20130816133848 && (echo b48fd42788eb54a7deb02d70c760573e949bc04d > /home/deploy/sites/n2b/application/demo/releases/20130816133848/REVISION)"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1178ms
  * 2013-08-16 09:38:49 executing `deploy:finalize_update'
    triggering before callbacks for `deploy:finalize_update'
  * 2013-08-16 09:38:49 executing `deploy:assets:symlink'
  * executing "rm -rf /home/deploy/sites/n2b/application/demo/releases/20130816133848/public/assets && mkdir -p /home/deploy/sites/n2b/application/demo/releases/20130816133848/public && mkdir -p /home/deploy/sites/n2b/application/demo/shared/assets && ln -s /home/deploy/sites/n2b/application/demo/shared/assets /home/deploy/sites/n2b/application/demo/releases/20130816133848/public/assets"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1236ms
  * 2013-08-16 09:38:51 executing `bundle:install'
    triggering before callbacks for `bundle:install'
  * 2013-08-16 09:38:51 executing `deploy:ruby_version'
****************************************
  * executing "ruby --version"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1023ms
ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-linux]
****************************************
  * executing "cd /home/deploy/sites/n2b/application/demo/releases/20130816133848 && bundle install --gemfile /home/deploy/sites/n2b/application/demo/releases/20130816133848/Gemfile --path /home/deploy/sites/n2b/application/demo/shared/bundle --deployment --quiet --without development test"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 2023ms
  * executing "chmod -R -- g+w /home/deploy/sites/n2b/application/demo/releases/20130816133848 && rm -rf -- /home/deploy/sites/n2b/application/demo/releases/20130816133848/public/system && mkdir -p -- /home/deploy/sites/n2b/application/demo/releases/20130816133848/public/ && ln -s -- /home/deploy/sites/n2b/application/demo/shared/system /home/deploy/sites/n2b/application/demo/releases/20130816133848/public/system && rm -rf -- /home/deploy/sites/n2b/application/demo/releases/20130816133848/log && ln -s -- /home/deploy/sites/n2b/application/demo/shared/log /home/deploy/sites/n2b/application/demo/releases/20130816133848/log && rm -rf -- /home/deploy/sites/n2b/application/demo/releases/20130816133848/tmp/pids && mkdir -p -- /home/deploy/sites/n2b/application/demo/releases/20130816133848/tmp/ && ln -s -- /home/deploy/sites/n2b/application/demo/shared/pids /home/deploy/sites/n2b/application/demo/releases/20130816133848/tmp/pids"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1143ms
    triggering after callbacks for `deploy:update_code'
  * 2013-08-16 09:38:55 executing `deploy:assets:precompile'
    triggering before callbacks for `deploy:assets:precompile'
  * 2013-08-16 09:38:55 executing `deploy:assets:update_asset_mtimes'
  * executing "[ -e /home/deploy/sites/n2b/application/demo/shared/assets/manifest* ] && cat /home/deploy/sites/n2b/application/demo/shared/assets/manifest* || echo"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1044ms
 ** Updating mtimes for ~64 assets...
    servers: ["rackspace"]
 ** scp upload #<StringIO:0x007f9c7482d8a0> -> /home/deploy/sites/n2b/application/demo/TOUCH_ASSETS
    [rackspace] /home/deploy/sites/n2b/application/demo/TOUCH_ASSETS
  * scp upload complete
  * executing "cat /home/deploy/sites/n2b/application/demo/TOUCH_ASSETS | while read asset; do touch -c -- \"$asset\"; done && rm -f -- /home/deploy/sites/n2b/application/demo/TOUCH_ASSETS"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1240ms
  * 2013-08-16 09:38:58 executing `deploy:copy_configs'
  * executing "cp /home/deploy/sites/n2b/application/demo/shared/config/* /home/deploy/sites/n2b/application/demo/releases/20130816133848/config/"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 999ms
  * executing "cd -- /home/deploy/sites/n2b/application/demo/releases/20130816133848 && RAILS_ENV=production RAILS_GROUPS=assets bundle exec rake assets:precompile"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 10589ms
  * executing "ls -1 /home/deploy/sites/n2b/application/demo/shared/assets/manifest* | wc -l"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1020ms
  * executing "ls /home/deploy/sites/n2b/application/demo/shared/assets/manifest*"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1010ms
  * executing "[ -e /home/deploy/sites/n2b/application/demo/shared/assets/manifest-1a0ef22a6d5592ac600ac4a660008092.json ] || mv -- /home/deploy/sites/n2b/application/demo/shared/assets/manifest* /home/deploy/sites/n2b/application/demo/shared/assets/manifest-1a0ef22a6d5592ac600ac4a660008092.json"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1051ms
  * executing "ls -x /home/deploy/sites/n2b/application/demo/releases"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1144ms
  * executing "cp -- /home/deploy/sites/n2b/application/demo/shared/assets/manifest-1a0ef22a6d5592ac600ac4a660008092.json /home/deploy/sites/n2b/application/demo/releases/shared/assets_manifest.json"
    servers: ["rackspace"]
    [rackspace] executing command
*** [err :: rackspace] cp:
*** [err :: rackspace] accessing `/home/deploy/sites/n2b/application/demo/releases/shared/assets_manifest.json'
*** [err :: rackspace] : Not a directory
*** [err :: rackspace] 
    command finished in 1041ms
*** [deploy:update_code] rolling back
  * executing "rm -rf /home/deploy/sites/n2b/application/demo/releases/20130816133848; true"
    servers: ["rackspace"]
    [rackspace] executing command
    command finished in 1092ms