fixes build without mobi

Author: Sherry520

Gemfile

@@ -1,22 +1,23 @@
 source 'https://rubygems.org'
 
+gem 'ffi', '1.16.3'
 gem 'rake'
-gem 'asciidoctor', '1.5.6.2'
+gem 'asciidoctor', '2.0.12'
 
 gem 'json'
 gem 'awesome_print'
 
-gem 'ttfunk', '= 1.5.1'
+gem 'ttfunk', '1.5.1'
+gem 'asciidoctor-fb2'
 gem 'asciidoctor-epub3', '1.5.0.alpha.9'
 gem 'asciidoctor-pdf', '1.5.0.alpha.16'
 gem 'asciidoctor-pdf-cjk', '~> 0.1.3'
-gem 'asciidoctor-pdf-cjk-kai_gen_gothic', '~> 0.1.1'
+gem 'asciidoctor-pdf-cjk-kai_gen_gothic', github: 'Sherry520/asciidoctor-pdf-cjk-kai_gen_gothic'
 
 gem 'coderay'
 gem 'pygments.rb'
 gem 'thread_safe'
 gem 'epubcheck-ruby'
-gem 'kindlegen'
+gem 'html-proofer'
 
-gem 'octokit'
-gem 'github_changelog_generator', github: 'Furtif/github-changelog-generator'
+#gem 'kindlegen', '3.1.1'