diff --git a/Gemfile.lock b/Gemfile.lock
index 9ea3f85..4c83198 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,13 +6,14 @@ GEM
     httpclient (2.6.0.1)
     json (2.3.0)
     multi_json (1.11.0)
-    puma (2.11.2)
-      rack (>= 1.1, < 2.0)
+    nio4r (2.3.1)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     pusher (0.14.5)
       httpclient (~> 2.5)
       multi_json (~> 1.0)
       signature (~> 0.1.8)
-    rack (1.6.0)
+    rack (1.6.13)
     rack-protection (1.5.3)
       rack
     redis (3.2.1)