diff --git a/Gemfile b/Gemfile
index 306f7aec..dcff4139 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,8 +8,8 @@ gem 'rails', '6.1.5'
 
 # Use SCSS for stylesheets
 gem 'sass-rails', '>= 5'
-# Use Uglifier as compressor for JavaScript assets
-gem 'uglifier', '>= 1.3.0'
+# Use Terser as compressor for JavaScript assets
+gem 'terser', '~> 1.1'
 
 # Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
 # gem 'turbolinks', '~> 5'
diff --git a/Gemfile.lock b/Gemfile.lock
index beb6d2b7..3ecf502e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -257,7 +257,7 @@ GEM
     matrix (0.4.2)
     method_source (1.0.0)
     mini_mime (1.1.2)
-    minitest (5.15.0)
+    minitest (5.16.1)
     msgpack (1.5.1)
     nested_form (0.3.2)
     net-scp (3.0.0)
@@ -286,8 +286,8 @@ GEM
       rspec-rails (>= 3.0.0)
     racc (1.6.0)
     rack (2.2.3.1)
-    rack-test (1.1.0)
-      rack (>= 1.0, < 3)
+    rack-test (2.0.2)
+      rack (>= 1.3)
     rails (6.1.5)
       actioncable (= 6.1.5)
       actionmailbox (= 6.1.5)
@@ -401,7 +401,7 @@ GEM
     spring-watcher-listen (2.0.1)
       listen (>= 2.7, < 4.0)
       spring (>= 1.2, < 3.0)
-    sprockets (4.0.3)
+    sprockets (4.1.1)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-es6 (0.9.2)
@@ -418,17 +418,19 @@ GEM
     stimulus-rails (1.0.4)
       railties (>= 6.0.0)
     temple (0.8.2)
+    terser (1.1.11)
+      execjs (>= 0.3.0, < 3)
     thor (1.2.1)
     tilt (2.0.10)
     timeliness (0.4.4)
     trix (0.10.1)
       rails
-    turbo-rails (7.1.1)
-      rails (>= 6.0.0)
+    turbo-rails (1.1.1)
+      actionpack (>= 6.0.0)
+      activejob (>= 6.0.0)
+      railties (>= 6.0.0)
     tzinfo (2.0.4)
       concurrent-ruby (~> 1.0)
-    uglifier (4.2.0)
-      execjs (>= 0.3.0, < 3)
     unicode-display_width (2.1.0)
     uniform_notifier (1.16.0)
     validates_timeliness (6.0.0.alpha1)
@@ -449,7 +451,7 @@ GEM
     wkhtmltopdf-binary (0.12.6.5)
     xpath (3.2.0)
       nokogiri (~> 1.8)
-    zeitwerk (2.5.4)
+    zeitwerk (2.6.0)
 
 PLATFORMS
   x86_64-darwin-18
@@ -516,9 +518,9 @@ DEPENDENCIES
   spring
   spring-watcher-listen (~> 2.0.0)
   sprockets-es6
+  terser (~> 1.1)
   trix
   tzinfo-data
-  uglifier (>= 1.3.0)
   validates_timeliness (= 6.0.0.alpha1)
   web-console (>= 3.3.0)
   webrick (= 1.7.0)
diff --git a/README.md b/README.md
index 3060171f..1795fefe 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,8 @@ The following are required to install competitions:
   * Storage should be configured locally or with AWS
   * Mailcatcher(https://mailcatcher.me) is used in the development environment for emails.
   * Postgres database
-  * RVM installed on server
+  * RVM installed on the server
+  # Yarn installed on the server
   * Capistrano for deployment
 
 
@@ -32,6 +33,8 @@ The following are required to install competitions:
 
 # Installation
 
+
+
 Configure the following files with your instance's attributes and store the files on the server.
 
 ```
diff --git a/config/environments/production.example.rb b/config/environments/production.example.rb
index 2fc00376..27dd2080 100644
--- a/config/environments/production.example.rb
+++ b/config/environments/production.example.rb
@@ -25,7 +25,8 @@
   config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
 
   # Compress JavaScripts and CSS.
-  config.assets.js_compressor = :uglifier
+  # changed from uglifier to terser with change to ES6.
+  config.assets.js_compressor = :terser
   # config.assets.css_compressor = :sass
 
   # Do not fallback to assets pipeline if a precompiled asset is missed.
diff --git a/config/environments/staging.example.rb b/config/environments/staging.example.rb
index d5dbfcfd..b5eec046 100644
--- a/config/environments/staging.example.rb
+++ b/config/environments/staging.example.rb
@@ -25,7 +25,8 @@
   config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
 
   # Compress JavaScripts and CSS.
-  config.assets.js_compressor = :uglifier
+  # changed from uglifier to terser with change to ES6.
+  config.assets.js_compressor = :terser
   # config.assets.css_compressor = :sass
 
   # Do not fallback to assets pipeline if a precompiled asset is missed.