diff --git a/Gemfile.lock b/Gemfile.lock
index 12e357b..8c7cab3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -57,6 +57,7 @@ GEM
     net-http-persistent (4.0.1)
       connection_pool (~> 2.2)
     netrc (0.11.0)
+    nio4r (2.5.7)
     nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
     ntlm-http (0.1.1)
@@ -82,7 +83,8 @@ GEM
       omniauth (~> 1.0)
       rack-openid (~> 1.3.1)
     public_suffix (2.0.5)
-    puma (3.9.1)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-accept (0.4.5)
       rack (>= 0.4)