diff --git a/Gemfile.lock b/Gemfile.lock
index 83be720..9430f1c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -159,6 +159,7 @@ GEM
     mysql2 (0.3.18)
     nenv (0.2.0)
     newrelic_rpm (3.14.0.305)
+    nio4r (2.3.1)
     nokogiri (1.5.11)
     notiffany (0.0.8)
       nenv (~> 0.1)
@@ -205,7 +206,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)
       slop (~> 3.4)
-    puma (2.15.3)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (1.4.7)
     rack-cache (1.5.1)
       rack (>= 0.4)