class Middleman::CoreExtensions::FrontMatter::FrontmatterManager

def clear_data(file)
  # Copied from Sitemap::Store#file_to_path, but without
  # removing the file extension
  file = File.expand_path(file, @app.root)
  prefix = @app.source_dir.sub(/\/$/, "") + "/"
  return unless file.include?(prefix)
  path = file.sub(prefix, "")
  @cache.delete(path)
end