id3-album.rb: fail if albumart.jpg not found

id3-album.rb

@@ -2,6 +2,8 @@
 
 # Install: kid3-common
 
+require "fileutils"
+
 $stdout.sync = true
 files = Dir.glob("*.mp3").sort
 
@@ -10,6 +12,11 @@ if files.empty?
   exit 1
 end
 
+unless File.exist?("albumart.jpg")
+  $stderr.puts "albumart.jpg not found"
+  exit 1
+end
+
 $stdout.write("Artist: ")
 artist = gets.chomp