class Xcodeproj::Project::Object::PBXShellScriptBuildPhase

associations with file references?
@todo Should ‘files`, `input_paths`, and `output_paths` be has_many

def initialize(*) 

def initialize(*)
  super
  self.files        ||= []
  self.input_paths  ||= []
  self.output_paths ||= []
  self.shell_path   ||= '/bin/sh'
  self.shell_script ||= ''
end