diff --git a/birthday/Gemfile.lock b/birthday/Gemfile.lock
index a551166..db2f826 100644
--- a/birthday/Gemfile.lock
+++ b/birthday/Gemfile.lock
@@ -110,7 +110,7 @@ GEM
     treetop (1.4.10)
       polyglot
       polyglot (>= 0.3.1)
-    tzinfo (0.3.33)
+    tzinfo (0.3.61)
     uglifier (1.2.4)
       execjs (>= 0.3.0)
       multi_json (>= 1.0.2)