diff --git a/Gemfile b/Gemfile
index 60b23eb..be18954 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ gem 'rails', '~> 5.0.0', '>= 5.0.0.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 3.12'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use CoffeeScript for .coffee assets and views
diff --git a/Gemfile.lock b/Gemfile.lock
index ac6e0e1..ea1d1b2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -66,7 +66,7 @@ GEM
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
-    libv8 (3.16.14.19-x86_64-linux)
+    libv8 (3.16.14.19)
     listen (3.0.8)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
@@ -84,7 +84,7 @@ GEM
     nio4r (1.2.1)
     nokogiri (1.8.0)
       mini_portile2 (~> 2.2.0)
-    puma (3.9.1)
+    puma (3.12.2)
     rack (2.0.3)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -184,7 +184,7 @@ DEPENDENCIES
   jbuilder (~> 2.5)
   jquery-rails
   listen (~> 3.0.5)
-  puma (~> 3.0)
+  puma (~> 3.12)
   rails (~> 5.0.0, >= 5.0.0.1)
   rspec-rails
   ruby-debug-ide