diff --git a/webapp/ruby/Gemfile.lock b/webapp/ruby/Gemfile.lock
index ea34192..4592568 100644
--- a/webapp/ruby/Gemfile.lock
+++ b/webapp/ruby/Gemfile.lock
@@ -17,7 +17,9 @@ GEM
     mysql2 (0.5.2)
     mysql2-cs-bind (0.0.7)
       mysql2
-    puma (3.12.0)
+    nio4r (2.5.7)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.0.5)
     rack-protection (2.0.3)
       rack