diff --git a/Gemfile.lock b/Gemfile.lock
index d90b1a2..5c01a80 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -137,11 +137,13 @@ GEM
     multi_test (0.1.2)
     mysql2 (0.5.2)
     netrc (0.11.0)
+    nio4r (2.5.8)
     nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
     pg (0.21.0)
     public_suffix (3.0.3)
-    puma (3.12.0)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (1.6.11)
     rack-test (0.6.3)
       rack (>= 1.0)