diff --git a/Gemfile.lock b/Gemfile.lock
index 1641277..5dc80e9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -35,12 +35,14 @@ GEM
     minitest (5.14.1)
     multi_json (1.13.1)
     multipart-post (2.0.0)
+    nio4r (2.5.8)
     pg (0.17.1)
     pry (0.9.12.6)
       coderay (~> 1.0)
       method_source (~> 0.8)
       slop (~> 3.4)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (1.6.12)
     rack-protection (1.5.5)
       rack