diff --git a/.gitignore b/.gitignore
index 1d6d2e34..6edb8af1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,4 @@ progit.fb2.zip
 progit-kf8.epub
 progit.mobi
 contributors.txt
+progit.mobi8
diff --git a/Gemfile b/Gemfile
index 751a5956..2211a4f2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -21,3 +21,4 @@ gem 'epubcheck-ruby'
 gem 'html-proofer'
 
 gem 'kindlegen', '3.1.1'
+gem 'nokogiri', '~> 1.13', '>= 1.13.10'