diff --git a/Gemfile b/Gemfile
index 848293e..227bbca 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ gem 'bcrypt', '~> 3.1.7'
 # Use sqlite3 as the database for Active Record
 gem 'mysql2'
 # 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 2d76225..7c2ff8e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -41,6 +41,7 @@ GEM
     addressable (2.6.0)
       public_suffix (>= 2.0.2, < 4.0)
     arel (8.0.0)
+    bcrypt (3.1.12)
     bcrypt (3.1.12-x86-mingw32)
     bindex (0.7.0)
     builder (3.2.3)
@@ -65,6 +66,7 @@ GEM
     crass (1.0.4)
     erubi (1.8.0)
     execjs (2.7.0)
+    ffi (1.10.0)
     ffi (1.10.0-x86-mingw32)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
@@ -81,12 +83,16 @@ GEM
     mini_mime (1.0.1)
     mini_portile2 (2.4.0)
     minitest (5.11.3)
+    mysql2 (0.5.2)
     mysql2 (0.5.2-x86-mingw32)
     nio4r (2.3.1)
+    nokogiri (1.10.3)
+      mini_portile2 (~> 2.4.0)
     nokogiri (1.10.3-x86-mingw32)
       mini_portile2 (~> 2.4.0)
     public_suffix (3.0.3)
-    puma (3.12.1)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -163,6 +169,7 @@ GEM
       nokogiri (~> 1.8)
 
 PLATFORMS
+  ruby
   x86-mingw32
 
 DEPENDENCIES
@@ -172,7 +179,7 @@ DEPENDENCIES
   coffee-rails (~> 4.2)
   jbuilder (~> 2.5)
   mysql2
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.1.3)
   sass-rails (~> 5.0)
   selenium-webdriver