diff --git a/Gemfile b/Gemfile
index e8d20ce9af..6ca57b6cbe 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,8 +2,8 @@ source 'https://rubygems.org'
 
 ruby '2.3.3'
 
-gem 'activesupport', '~> 4.2.8'
-gem 'activerecord', '~> 4.2.8'
+gem 'activesupport', '~> 5.0.3'
+gem 'activerecord', '~> 5.0.3'
 
 gem 'bugsnag', '~> 5.3'
 gem 'faraday'
@@ -21,7 +21,7 @@ gem 'redcarpet', '~> 3.1'
 gem 'rouge', '~> 2.0.5'
 gem 'sinatra', '~> 2.0.0', require: 'sinatra/base'
 gem 'sinatra-contrib', '~> 2.0.0'
-gem 'sidekiq'
+gem 'sidekiq', '~> 4.2.10'
 gem 'trackler', '~> 2.1.0'
 gem 'will_paginate'
 gem 'will_paginate-bootstrap'
diff --git a/Gemfile.lock b/Gemfile.lock
index a3b8cbc4d6..8307e655ce 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,23 +1,22 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activemodel (4.2.8)
-      activesupport (= 4.2.8)
-      builder (~> 3.1)
-    activerecord (4.2.8)
-      activemodel (= 4.2.8)
-      activesupport (= 4.2.8)
-      arel (~> 6.0)
-    activesupport (4.2.8)
+    activemodel (5.0.3)
+      activesupport (= 5.0.3)
+    activerecord (5.0.3)
+      activemodel (= 5.0.3)
+      activesupport (= 5.0.3)
+      arel (~> 7.0)
+    activesupport (5.0.3)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (~> 0.7)
       minitest (~> 5.1)
-      thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
     addressable (2.4.0)
     approvals (0.0.22)
       nokogiri (~> 1.6)
       thor (~> 0.18)
-    arel (6.0.4)
+    arel (7.1.4)
     ast (2.2.0)
     autoprefixer-rails (6.3.5)
       execjs
@@ -26,7 +25,6 @@ GEM
       autoprefixer-rails (>= 5.2.1)
       sass (>= 3.3.4)
     bugsnag (5.3.1)
-    builder (3.2.3)
     capybara (2.6.2)
       addressable
       mime-types (>= 1.16)
@@ -48,8 +46,8 @@ GEM
       sass (>= 3.3.0, < 3.5)
     compass-import-once (1.0.5)
       sass (>= 3.2, < 3.5)
-    concurrent-ruby (1.0.1)
-    connection_pool (2.2.0)
+    concurrent-ruby (1.0.5)
+    connection_pool (2.2.1)
     coveralls (0.8.13)
       json (~> 1.8)
       simplecov (~> 0.11.0)
@@ -131,7 +129,7 @@ GEM
       ffi (>= 0.5.0)
     rb-readline (0.5.3)
     redcarpet (3.3.4)
-    redis (3.2.2)
+    redis (3.3.3)
     rouge (2.0.5)
     rubocop (0.36.0)
       parser (>= 2.3.0.0, < 3.0)
@@ -142,9 +140,10 @@ GEM
     rubypants (0.6.0)
     rubyzip (1.2.1)
     sass (3.4.21)
-    sidekiq (4.1.1)
+    sidekiq (4.2.10)
       concurrent-ruby (~> 1.0)
       connection_pool (~> 2.2, >= 2.2.0)
+      rack-protection (>= 1.5.0)
       redis (~> 3.2, >= 3.2.1)
     simplecov (0.11.2)
       docile (~> 1.1.0)
@@ -187,8 +186,8 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  activerecord (~> 4.2.8)
-  activesupport (~> 4.2.8)
+  activerecord (~> 5.0.3)
+  activesupport (~> 5.0.3)
   approvals
   bootstrap-sass
   bugsnag (~> 5.3)
@@ -220,7 +219,7 @@ DEPENDENCIES
   rouge (~> 2.0.5)
   rubocop (= 0.36.0)
   sass
-  sidekiq
+  sidekiq (~> 4.2.10)
   simplecov
   sinatra (~> 2.0.0)
   sinatra-contrib (~> 2.0.0)
diff --git a/api/v1.rb b/api/v1.rb
index 7135e81e65..d1e9d811b8 100644
--- a/api/v1.rb
+++ b/api/v1.rb
@@ -12,6 +12,10 @@ module ExercismAPI
 
 module ExercismAPI
   class App < Sinatra::Base
+    configure do
+      after { ActiveRecord::Base.connection.close }
+    end
+
     use Routes::Exercises
     use Routes::Iterations
     use Routes::Submissions
diff --git a/app.rb b/app.rb
index 816d77d7e2..20095c013b 100644
--- a/app.rb
+++ b/app.rb
@@ -20,6 +20,7 @@ module ExercismWeb
   class App < Sinatra::Base
     configure do
       use Rack::Session::Cookie, secret: ENV.fetch('SESSION_SECRET', DEFAULT_SESSION_KEY)
+      after { ActiveRecord::Base.connection.close }
     end
 
     if settings.development?
diff --git a/config.ru b/config.ru
index bec5932fac..df04445946 100644
--- a/config.ru
+++ b/config.ru
@@ -25,7 +25,6 @@ require 'api/v1'
 
 ENV['RACK_ENV'] ||= 'development'
 
-use ActiveRecord::ConnectionAdapters::ConnectionManagement
 use Rack::MethodOverride
 run Rack::URLMap.new(
   "/" => ExercismWeb::App,
diff --git a/lib/exercism/homework.rb b/lib/exercism/homework.rb
index df6b7736bc..7eade9f16d 100644
--- a/lib/exercism/homework.rb
+++ b/lib/exercism/homework.rb
@@ -46,7 +46,10 @@ def status(language)
 
   def extract(sql)
     UserExercise.connection.execute(sql).each_with_object(empty_hash) do |row, exercises|
-      exercises[row['language']] << { 'slug' => row['slug'], 'state' => row['archived'] == 't' ? 'archived' : 'active' }
+      exercises[row['language']] << {
+        'slug' => row['slug'],
+        'state' => row['archived'] ? 'archived' : 'active'
+      }
     end
   end
 
diff --git a/lib/exercism/team.rb b/lib/exercism/team.rb
index 56192b510b..6f5c9f46b1 100644
--- a/lib/exercism/team.rb
+++ b/lib/exercism/team.rb
@@ -119,7 +119,7 @@ def potential_members(comma_delimited_names)
 
   def normalize_slug
     return unless slug
-    self.slug = slug.tr('_', '-').parameterize('-')
+    self.slug = slug.tr('_', '-').parameterize(separator: '-')
   end
 
   def provide_default_slug
diff --git a/test/active_record_helper.rb b/test/active_record_helper.rb
index d1cd8dace9..c3b042693e 100644
--- a/test/active_record_helper.rb
+++ b/test/active_record_helper.rb
@@ -1,6 +1,5 @@
 ENV['RACK_ENV'] = 'test'
 require_relative './test_helper'
-gem 'activerecord', '~> 4.0'
 require 'active_record'
 require 'database_cleaner'
 require 'db/connection'
diff --git a/test/exercism/use_cases/creates_comment_test.rb b/test/exercism/use_cases/creates_comment_test.rb
index 12087f4d79..2b85cf1052 100644
--- a/test/exercism/use_cases/creates_comment_test.rb
+++ b/test/exercism/use_cases/creates_comment_test.rb
@@ -41,7 +41,7 @@ def test_should_return_invalid_comment_if_invalid
   def test_empty_nit_does_not_get_created
     nitpicker = User.new(username: 'alice')
     CreatesComment.new(submission.id, nitpicker, '').create
-    assert_equal 0, submission.comments(true).count
+    assert_equal 0, submission.comments.reload.count
   end
 
   def test_nitpicking_archived_exercise_does_not_reactivate_it