diff --git a/Gemfile.lock b/Gemfile.lock
index cabff89..d3d0a14 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -23,6 +23,7 @@ GEM
     mime-types (1.25.1)
     minitest (5.8.3)
     moneta (0.7.20)
+    nio4r (2.3.1)
     padrino (0.12.4)
       padrino-admin (= 0.12.4)
       padrino-cache (= 0.12.4)
@@ -64,7 +65,8 @@ GEM
       slop (~> 3.4)
     pry-padrino (0.1.2)
       pry (>= 0.8)
-    puma (2.15.3)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (1.6.4)
     rack-protection (1.5.3)
       rack