diff --git a/Gemfile.lock b/Gemfile.lock
index e0ae40c..d925687 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -70,8 +70,8 @@ GEM
       thor (~> 1.0)
     concurrent-ruby (1.1.9)
     crass (1.0.6)
-    debug (1.2.0)
-      irb
+    debug (1.2.1)
+      irb (>= 1.3.6)
       reline (>= 0.2.7)
     diff-lcs (1.4.4)
     erubi (1.10.0)