Adding html-proofer
diff --git a/Gemfile b/Gemfile
index dfe83cd..205a395 100644
--- a/Gemfile
+++ b/Gemfile
@@ -30,5 +30,4 @@
   gem 'jekyll-asciidoc', '~> 2.1.1'
 end
 
-# TODO: check if used if not need to be deleted
-#gem "html-proofer"
+gem "html-proofer"