diff --git a/.travis.yml b/.travis.yml
index 82cf996..255108e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,37 +1,37 @@
 language: ruby
 
-before_install:
-  # Workaround for https://github.com/travis-ci/travis-ci/issues/8969
-  - gem update --system
-
 rvm:
-  - 2.2
-  - 2.3
   - 2.4
   - 2.5
   - 2.6
+  - 2.7
 
 env:
   - RAILS_VERSION=4.2
   - RAILS_VERSION=5.0
   - RAILS_VERSION=5.1
   - RAILS_VERSION=5.2
+  - RAILS_VERSION=6.0
 
 matrix:
+  include:
+    - rvm: 2.4
+      before_install:
+        # Source: <https://docs.travis-ci.com/user/languages/ruby/#bundler-20>
+        - gem update --system '2.7.8' --no-document
+        - gem uninstall -v '>= 2' -i $(rvm gemdir)@global -ax bundler || true
+        - gem install bundler -v '< 2' --no-document
   exclude:
-    - rvm: 2.2
-      env: RAILS_VERSION=5.0
-    - rvm: 2.2
-      env: RAILS_VERSION=5.1
-    - rvm: 2.2
-      env: RAILS_VERSION=5.2
-    - rvm: 2.5
-      env: RAILS_VERSION=4.2
-    - rvm: 2.5
-      env: RAILS_VERSION=5.0
+    - rvm: 2.4
+      env: RAILS_VERSION=6.0
     - rvm: 2.6
       env: RAILS_VERSION=4.2
     - rvm: 2.6
       env: RAILS_VERSION=5.0
+    - rvm: 2.7
+      env: RAILS_VERSION=4.2
+    - rvm: 2.7
+      env: RAILS_VERSION=5.0
 
 sudo: false
+cache: bundler
diff --git a/Gemfile b/Gemfile
index 45fa91c..84535a4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,6 +5,6 @@ source "http://rubygems.org"
 # development dependencies will be added by default to the :development group.
 gemspec
 
-version = ENV['RAILS_VERSION'] || "4.0"
+version = ENV['RAILS_VERSION'] || "4.2"
 
 eval_gemfile File.expand_path("../gemfiles/#{version}.gemfile", __FILE__)
diff --git a/gemfiles/6.0.gemfile b/gemfiles/6.0.gemfile
new file mode 100644
index 0000000..c322737
--- /dev/null
+++ b/gemfiles/6.0.gemfile
@@ -0,0 +1,12 @@
+gem 'puma'
+gem 'jquery-rails'
+gem 'jquery-ui-rails'
+gem 'ancestry'
+gem 'sqlite3', '~> 1.4'
+
+gem 'activeadmin'
+gem 'devise'
+gem 'rails', '~> 6.0.0'
+gem 'sass-rails'
+
+# vim: ft=ruby
diff --git a/spec/dummy/app/assets/config/manifest.js b/spec/dummy/app/assets/config/manifest.js
new file mode 100644
index 0000000..e0020d0
--- /dev/null
+++ b/spec/dummy/app/assets/config/manifest.js
@@ -0,0 +1,2 @@
+//= link_directory ../javascripts .js
+//= link_directory ../stylesheets .css
\ No newline at end of file