chore: Add Travis configuration

.travis.yml

@@ -0,0 +1,26 @@
+sudo: false
+language: ruby
+cache: bundler
+
+before_install:
+  - gem update bundler
+
+before_script:
+  - bundle update
+
+script:
+  - bundle exec rake spec
+
+env:
+  - rails=4.2.0
+  - rails=5.0.0
+
+rvm:
+  - 2.1
+  - 2.2.5
+  - 2.3.1
+
+matrix:
+  exclude:
+    - env: rails=5.0.0
+      rvm: 2.1

Gemfile

@@ -1,3 +1,8 @@
+ENV['rails'] ||= '5.0.0'
+
 source 'https://rubygems.org'
 
+# use Rails version specified by environment
+gem 'rails', "~> #{ENV['rails']}"
+
 gemspec

doorkeeper-openid_connect.gemspec

@@ -23,6 +23,5 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency 'rspec-rails'
   spec.add_development_dependency 'factory_girl'
-  spec.add_development_dependency 'rails'
   spec.add_development_dependency 'sqlite3'
 end