class Sprockets::Manifest

def remove(filename)


manifest.remove("application-2e8e9a7c6b0aafa0c9bdeec90ea30213.js")

be the name with any directory path.
Removes file from directory and from manifest. `filename` must 
def remove(filename)
  path = File.join(dir, filename)
  logical_path = files[filename]['logical_path']
  if assets[logical_path] == filename
    assets.delete(logical_path)
  end
  files.delete(filename)
  FileUtils.rm(path) if File.exist?(path)
  save
  logger.warn "Removed #{filename}"
  nil
end