只要在deploy.rb裡改這段

# Default branch is :master, we deploy current branch
ask :branch, `git rev-parse --abbrev-ref HEAD`.chomp
set :branch, `git rev-parse --abbrev-ref HEAD`.chomp

if `git rev-parse --abbrev-ref HEAD`.chomp == "chiduino-prod"
  set :deploy_to, '/home/deploy/apps/chiduino'
elsif `git rev-parse --abbrev-ref HEAD`.chomp == "chiduino-dev"
  set :deploy_to, '/home/deploy/apps/chiduino-dev'
else
  break
end

這樣以後部署時就會抓當前的branch~

如果想要自行指定 可以打 branch=my_branch cap production deploy