Gemfile

source 'https://rubygems.org'

gem 'jekyll'
gem 'maruku'
gem 'rake'
gem 'sass'
gem 'compass'
gem 'coffee-script'

Rakefile

desc "compile and run the site"
task :default do
  pids = [
    spawn("jekyll"), # put `auto: true` in your _config.yml
    spawn("compass watch"), # asuming we initiate compass on root folder
    spawn("coffee -b -w -o javascripts -c assets/*.coffee")
  ]

  trap "INT" do
    Process.kill "INT", *pids
    exit 1
  end

  loop do
    sleep 1
  end
end