Updated for Capistrano 3.

deploy.rb

# encoding: UTF-8

# Place in config/deploy.rb

namespace :rails do
  desc "Open the rails console on each of the remote servers"
  task :console do
    on roles(:app) do |host| #does it for each host, bad.
      rails_env = fetch(:stage)
      execute_interactively "ruby #{current_path}/script/rails console #{rails_env}"  
    end
  end

  desc "Open the rails dbconsole on each of the remote servers"
  task :dbconsole do
    on roles(:db) do |host| #does it for each host, bad.
      rails_env = fetch(:stage)
      execute_interactively "ruby #{current_path}/script/rails dbconsole #{rails_env}"  
    end
  end

  def execute_interactively(command)
    user = fetch(:user)
    port = fetch(:port) || 22
    exec "ssh -l #{user} #{host} -p #{port} -t 'cd #{deploy_to}/current && #{command}'"
  end
end