capistrano multistage deploy_to(fixed)

staging.rb

set(:deploy_to) { "/var/www/#{application}-#{rails_env}" }
set(:releases_path) { File.join(deploy_to, version_dir) }
set(:shared_path) { File.join(deploy_to, shared_dir) }
set(:current_path) { File.join(deploy_to, current_dir) }
set(:release_path) { File.join(releases_path, release_name) }

# unicornを使っているなら以下も
set(:unicorn_config) { "#{current_path}/config/unicorn.rb" }
set(:unicorn_pid) { "#{current_path}/tmp/pids/unicorn.pid" }