diff --git a/Gemfile.lock b/Gemfile.lock
index c184875740..9c4dcdac94 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -233,6 +233,7 @@ GEM
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rake (12.0.0)
+    rb-readline (0.5.3)
     recog (2.1.4)
       nokogiri
     redcarpet (3.4.0)