diff --git a/Gemfile.lock b/Gemfile.lock
index 682c357..da1e9db 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -14,6 +14,7 @@ GEM
       execjs
     coffee-script-source (1.12.2)
     colorator (0.1)
+    concurrent-ruby (1.1.10)
     ethon (0.10.1)
       ffi (>= 1.3.0)
     execjs (2.7.0)
@@ -131,14 +132,13 @@ GEM
     terminal-table (1.7.3)
       unicode-display_width (~> 1.1.1)
     thor (0.19.4)
-    thread_safe (0.3.5)
     tilt (1.3.7)
     toml (0.1.2)
       parslet (~> 1.5.0)
     typhoeus (0.8.0)
       ethon (>= 0.8.0)
-    tzinfo (1.2.2)
-      thread_safe (~> 0.1)
+    tzinfo (2.0.5)
+      concurrent-ruby (~> 1.0)
     tzinfo-data (1.2016.10)
       tzinfo (>= 1.0.0)
     unicode-display_width (1.1.2)