diff --git a/Gemfile.lock b/Gemfile.lock
index f1fcb1b..4cd7aa0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -12,6 +12,7 @@ GEM
   specs:
     byebug (10.0.2)
     coderay (1.1.2)
+    concurrent-ruby (1.1.10)
     diff-lcs (1.3)
     et-orbi (1.1.6)
       tzinfo
@@ -67,11 +68,10 @@ GEM
       rack (~> 2.0)
       rack-protection (= 2.0.4)
       tilt (~> 2.0)
-    thread_safe (0.3.6)
     tilt (2.0.8)
     timecop (0.9.1)
-    tzinfo (1.2.5)
-      thread_safe (~> 0.1)
+    tzinfo (2.0.5)
+      concurrent-ruby (~> 1.0)
     vegas (0.1.11)
       rack (>= 1.0.0)