Fix filenames with double-quotes

spec/util_spec.cr

@@ -0,0 +1,9 @@
+require "../src/util"
+require "./spec_helper"
+
+describe Muse::Dl::Util do
+  it "should sanitize filenames properly" do
+    fn = Muse::Dl::Util.slug_filename("Hello world - \" :A$3, a story; a poem|chapter")
+    fn.should eq "Hello world - - -A-3, a story- a poem-chapter"
+  end
+end

src/util.cr

@@ -2,7 +2,7 @@ module Muse::Dl
   class Util
     # Generates a safe filename
     def self.slug_filename(input : String)
-      input.strip.tr("\u{202E}%$|:;/\t\r\n\\", "-")
+      input.strip.tr("\u{202E}%$|:;/\"\t\r\n\\", "-")
     end
   end
 end