Unicorn + Capistrano 3 + RVM + GIT

deploy.rb

set :application, '<%= application %>'
set :repo_url, '<%= repo_url %>'
set :user, '<%= user %>'

# ask :branch, proc { `git rev-parse --abbrev-ref HEAD`.chomp }

set :deploy_to, "<%= deploy_to %>"
set :scm, :git

set :format, :pretty
# set :log_level, :debug
# set :pty, true

set :linked_files, %w{config/application.yml config/database.yml}
set :linked_dirs, %w{log tmp/pids tmp/cache tmp/sockets vendor/bundle public/system}

# set :default_env, { path: "/opt/ruby/bin:$PATH" }
set :keep_releases, 5

namespace :deploy do

  desc 'Start application'
  task :start do
    on roles(:app) do |host|
      within current_path do
        execute :bundle, :exec, :unicorn_rails, '-c', "#{current_path}/config/unicorn.rb", '-D'
      end
    end
  end

  desc 'Stop application'
  task :stop do
    on roles(:app) do |host|
      execute :kill, "`cat #{current_path}/tmp/pids/unicorn.pid`"
    end
  end

  desc 'Gracefully stop application'
  task :graceful_stop do
    on roles(:app) do |host|
      execute :kill, :QUIT, "`cat #{current_path}/tmp/pids/unicorn.pid`"
    end
  end

  desc 'Gracefully reload application'
  task :reload do
    on roles(:app) do |host|
      execute :kill, :USR2, "`cat #{current_path}/tmp/pids/unicorn.pid`"
    end
  end

  desc 'Restart application'
  task :restart do
    invoke 'deploy:stop'
    invoke 'deploy:start'
  end

  before :start, 'rvm:hook'

  after :restart, :clear_cache do
    # on roles(:web), in: :groups, limit: 3, wait: 10 do
      # Here we can do anything such as:
      # within release_path do
      #   execute :rake, 'cache:clear'
      # end
    # end
  end

  after :finishing, 'deploy:cleanup'
end