diff --git a/Gemfile.lock b/Gemfile.lock
index e368ec2..3729a2a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -216,6 +216,7 @@ GEM
     ngannotate-rails (1.2.2)
       execjs
       rails (>= 3.1)
+    nio4r (2.5.8)
     nokogiri (1.10.4)
       mini_portile2 (~> 2.4.0)
     nokogumbo (1.5.0)
@@ -234,7 +235,8 @@ GEM
       ttfunk (~> 1.5)
     prawn-table (0.2.2)
       prawn (>= 1.3.0, < 3.0.0)
-    puma (3.12.0)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (1.6.11)
     rack-rewrite (1.5.1)
     rack-test (0.6.3)