diff --git a/Gemfile b/Gemfile
index 0eb1699..09d4316 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '~> 5.1.4'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index 823fa0f..7fc551e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -18,8 +18,8 @@ GEM
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.1.6.2)
-      activesupport (= 5.1.6.2)
+    actionview (5.1.6)
+      activesupport (= 5.1.6)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
@@ -50,13 +50,13 @@ GEM
       execjs
     coffee-script-source (1.12.2)
     concurrent-ruby (1.1.5)
-    crass (1.0.4)
-    erubi (1.7.1)
+    crass (1.0.5)
+    erubi (1.9.0)
     execjs (2.7.0)
     ffi (1.9.25)
     globalid (0.4.1)
       activesupport (>= 4.2.0)
-    i18n (1.0.1)
+    i18n (1.7.0)
       concurrent-ruby (~> 1.0)
     jbuilder (2.7.0)
       activesupport (>= 4.2.0)
@@ -65,7 +65,7 @@ GEM
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
       ruby_dep (~> 1.2)
-    loofah (2.2.3)
+    loofah (2.4.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.0)
@@ -73,12 +73,13 @@ GEM
     method_source (0.9.0)
     mini_mime (1.0.0)
     mini_portile2 (2.4.0)
-    minitest (5.11.3)
+    minitest (5.13.0)
     multi_json (1.13.1)
     nio4r (2.3.1)
-    nokogiri (1.10.3)
+    nokogiri (1.10.7)
       mini_portile2 (~> 2.4.0)
-    puma (3.11.4)
+    puma (4.3.1)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.0.0)
       rack (>= 1.0, < 3)
@@ -97,8 +98,8 @@ GEM
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)
-    rails-html-sanitizer (1.0.4)
-      loofah (~> 2.2, >= 2.2.2)
+    rails-html-sanitizer (1.3.0)
+      loofah (~> 2.3)
     railties (5.1.6)
       actionpack (= 5.1.6)
       activesupport (= 5.1.6)
@@ -161,7 +162,7 @@ DEPENDENCIES
   coffee-rails (~> 4.2)
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.1.4)
   sass-rails (~> 5.0)
   spring