diff --git a/Gemfile b/Gemfile
index 29acb873810d26479e1ff7972d4b4fe8676aa814..84f8492211cc16db7added0f23e6cd6bcca1796a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,6 +2,7 @@
 
 source "https://rubygems.org"
 
+gem "webrick"
 gem "rackup"
 gem "ostruct"
 gem "csv"