diff --git a/Gemfile.lock b/Gemfile.lock
index 21d6dd9..00cf39a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -114,6 +114,7 @@ GEM
     mini_portile2 (2.0.0)
     minitest (5.8.4)
     multi_json (1.11.2)
+    nio4r (2.5.2)
     nokogiri (1.6.7.2)
       mini_portile2 (~> 2.0.0.rc2)
     orm_adapter (0.5.0)
@@ -127,7 +128,8 @@ GEM
       pry (~> 0.10)
     pry-rails (0.3.4)
       pry (>= 0.9.10)
-    puma (3.12.4)
+    puma (5.6.2)
+      nio4r (~> 2.0)
     quiet_assets (1.1.0)
       railties (>= 3.1, < 5.0)
     rack (1.6.4)