diff --git a/.gitignore b/.gitignore
index 5a7cd82..cec5779 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,7 @@
 .ruby-version
 .bundle
 Gemfile.lock
+gemfiles/*.lock
 html
 pkg
 .idea
diff --git a/.travis.yml b/.travis.yml
index 786f6ae..41b4d4a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,17 @@
+rvm:
+  - 2.2
+  - 2.3
+  - 2.4
+
+gemfile:
+  - gemfiles/rails_4.2.gemfile
+  - gemfiles/rails_5.0.gemfile
+  - gemfiles/rails_5.1.gemfile
+
+matrix:
+  exclude:
+    - rvm: 2.4
+      gemfile: gemfiles/rails_4.2.gemfile
+
 language: ruby
 cache: bundler
-rvm:
-  - 2.1.2
-  - 2.0.0
-  - 1.9.3
diff --git a/gemfiles/rails_4.2.gemfile b/gemfiles/rails_4.2.gemfile
new file mode 100644
index 0000000..3f3ebec
--- /dev/null
+++ b/gemfiles/rails_4.2.gemfile
@@ -0,0 +1,5 @@
+source "https://rubygems.org"
+
+gem "rails", "~> 4.2.0"
+
+gemspec :path => "../"
diff --git a/gemfiles/rails_5.0.gemfile b/gemfiles/rails_5.0.gemfile
new file mode 100644
index 0000000..9678e90
--- /dev/null
+++ b/gemfiles/rails_5.0.gemfile
@@ -0,0 +1,5 @@
+source "https://rubygems.org"
+
+gem "rails", "~> 5.0.0"
+
+gemspec :path => "../"
diff --git a/gemfiles/rails_5.1.gemfile b/gemfiles/rails_5.1.gemfile
new file mode 100644
index 0000000..edd27fb
--- /dev/null
+++ b/gemfiles/rails_5.1.gemfile
@@ -0,0 +1,5 @@
+source "https://rubygems.org"
+
+gem "rails", "~> 5.1.0"
+
+gemspec :path => "../"
diff --git a/sanitize-rails.gemspec b/sanitize-rails.gemspec
index 415ea75..1e37fde 100644
--- a/sanitize-rails.gemspec
+++ b/sanitize-rails.gemspec
@@ -17,6 +17,6 @@ Gem::Specification.new do |s|
   s.require_paths = ["lib"]
   s.files         = `git ls-files`.split("\n")
 
-  s.add_dependency "rails",    ">= 3.0"
-  s.add_dependency "sanitize", ">= 3.0"
+  s.add_dependency "rails"
+  s.add_dependency "sanitize"
 end