class Xcodeproj::Project::Object::PBXNativeTarget

def add_resources(resource_file_references)
  resource_file_references.each do |file|
    next if resources_build_phase.include?(file)
    build_file = project.new(PBXBuildFile)
    build_file.file_ref = file
    resources_build_phase.files << build_file
  end
end