diff --git a/Gemfile b/Gemfile
index 5ddbad1..388ef00 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,7 +7,7 @@ gem 'jquery-rails'
 gem 'jbuilder', '~> 1.2'
 gem 'spreadsheet'
 gem 'devise'
-gem 'nokogiri'
+gem 'nokogiri', '>= 1.13.6'
 gem 'sass-rails', '~> 4.0.3'
 gem 'bootstrap-sass', '~> 3.1.1'
 gem 'bootstrap-datepicker-rails'