Capistrano Deployment in Rails 3 (via the rvm-capistrano gem)

• Go to your project path.
• Add gem 'rvm-capistrano' to your Gemfile
• Run bundle install for installing the gem
• Run the command capify . This will create
• [add] writing './Capfile'
• [add] writing './config/deploy.rb'
• [done] capified!

• Modify the setting in your ./config/deploy.rb, sample settings is provided below 

require "rvm/capistrano"
set :application, "My Test App"            # Your application name
set :domain, "testapp.com"                 # Domain name for your app
set :repository,  "git@github.com:test/test.git" # The code repository url
set :user, "test_user"           # The ssh user that has access to your server
default_run_options[:pty] = true
set :use_sudo, false

set :scm, :git
set :deploy_via, :remote_cache
set :deploy_to, "/home/test/test_project_production"  # Server path to which the code is to be deployed

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

# Add RVM's lib directory to the load path.
$:.unshift(File.expand_path('./lib', ENV['rvm_path']))

# Load RVM's capistrano plugin.    
set :rvm_ruby_string, '1.9.2'          # The ruby version in your server             
set :rvm_type, :user                   # Don't use system-wide RVM

# Various task that needs to be executed during the deployment process.
namespace :deploy do
  task :start do 
    run "sudo /etc/init.d/nginx start" 
  end
  task :stop do 
    run "sudo /etc/init.d/nginx stop"    
  end
  task :restart, :roles => :app, :except => { :no_release => true } do
    run "sudo /etc/init.d/nginx restart"    
  end
  
  desc "Copies database credentials"
  task :copy_db_credentials do
    run "cp #{shared_path}/credentials/database.yml #{release_path}/config/database.yml"
  end
  
  desc "install the necessary prerequisites"
  task :bundle_install do
    run "cd #{release_path} && bundle install"
  end

end

before "deploy:assets:precompile", "deploy:bundle_install"
before "deploy:assets:precompile", "deploy:copy_db_credentials"
# after "deploy:update_code", "deploy:bundle_install"

after "deploy", "deploy:migrate", "deploy:cleanup"

In your ./Capfile uncomment the line load 'deploy/assets'

Now you need to do some configuration in your server:
• Login into the server with root access
• For allowing test_user to run sudo commands without password we need to do the following changes
• Run command: visudo
• Add the following line test_user ALL= NOPASSWD: /etc/init.d/* after 
• ## Allow root to run any commands anywhere
• root    ALL=(ALL)       ALL
• save and exit the file 
Now from your local machine project path run the following commands
• cap deploy:setup
• cap deploy:check
• cap deploy
Note: You may get error saying "cannot create releases folder" in server
• Login to your server go to your project path /home/test/test_project_production you will be seeing a "shared" folder  create another folder "releases" 
• Go to "shared" folder create directories "system", "log", "credentials"
• In credentials folder add your database.yml file with DB settings.


Thats it!!.... Again Run the cap deploy . Your code will be successfully deployed to the server. :)

Helpful links are: Deploying with Capistrano    Capistrano Tasks