diff --git a/Gemfile.lock b/Gemfile.lock
index 86dae79..f111428 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -4,6 +4,7 @@ GEM
     addressable (2.3.8)
     bson (4.2.0)
     buftok (0.2.0)
+    concurrent-ruby (1.1.10)
     daemons (1.2.2)
     domain_name (0.5.20180417)
       unf (>= 0.0.5, < 1.0.0)
@@ -56,7 +57,7 @@ GEM
       daemons (~> 1.0, >= 1.0.9)
       eventmachine (~> 1.0)
       rack (~> 1.0)
-    thread_safe (0.3.5)
+    thread_safe (0.3.6)
     tilt (1.4.1)
     twitter (5.14.0)
       addressable (~> 2.3)
@@ -71,8 +72,8 @@ GEM
       simple_oauth (~> 0.3.0)
     tz (0.0.1)
       tzinfo
-    tzinfo (1.2.2)
-      thread_safe (~> 0.1)
+    tzinfo (2.0.5)
+      concurrent-ruby (~> 1.0)
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.6)