$ PATH=/opt/ghost-git/gems/sass/bin:/opt/ghost-git/gems/bourbon/bin:"$PATH" grunt
Running "sass:compress" (sass) task
/usr/lib/ruby/1.9.1/rubygems/dependency.rb:247:in `to_specs': Could not find sass (>= 0) amongst [] (Gem::LoadError)
	from /usr/lib/ruby/1.9.1/rubygems/dependency.rb:256:in `to_spec'
	from /usr/lib/ruby/1.9.1/rubygems.rb:1231:in `gem'
	from /opt/ghost-git/gems/sass/bin/sass:22:in `<main>'
Warning:  Use --force to continue.