pass_manifest.rb

require 'digest/sha1'
require 'json'

file_names =  Dir.entries(".").select do |f|
  f.end_with?(".png") || f == "pass.json"
end

manifest = {}
file_names.each do |f|
  manifest[f] = Digest::SHA2.hexdigest(File.read(f))
end

File.open("manifest.json", "w") do |f|
  f.write(JSON.pretty_generate(manifest))
end