diff --git a/Gemfile.lock b/Gemfile.lock
index 9119872..75729a5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -234,6 +234,7 @@ GEM
     net-ssh (5.0.1)
     net-ssh-gateway (2.0.0)
       net-ssh (>= 4.0.0)
+    nio4r (2.5.2)
     nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
     notiffany (0.1.1)
@@ -253,7 +254,8 @@ GEM
       method_source (~> 0.8)
       slop (~> 3.4)
     public_suffix (3.0.2)
-    puma (3.11.4)
+    puma (4.3.1)
+      nio4r (~> 2.0)
     rack (1.6.11)
     rack-contrib (1.8.0)
       rack (~> 1.4)