我需要www-data用户从 nginx/php5-fpm编译 scss
命令：
compass compile sass/screen.scss --config config.rb --boring
结果：
/usr/local/rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/rubygems/dependency.rb:298:in `to_specs': Could not find 'compass' (>= 0) among 14 total gem(s) (Gem::LoadError)
from /usr/local/rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/rubygems/dependency.rb:309:in `to_spec'
from /usr/local/rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/rubygems/core_ext/kernel_gem.rb:53:in `gem'
from /usr/bin/compass:22:in `<main>'
from /usr/bin/ruby_executable_hooks:15:in `eval'
from /usr/bin/ruby_executable_hooks:15:in `<main>'
UPD1
$ gem list
*** LOCAL GEMS ***
...
compass (1.1.0.alpha.3, 1.0.1)
compass-core (1.1.0.alpha.3, 1.0.1)
compass-import-once (1.0.5)
...