test against stable rails versions

.gitignore

@@ -11,3 +11,6 @@ test/dummy/.sass-cache
 !/test/sandbox/.gitkeep
 
 .ruby-version
+
+Gemfile.lock
+gemfiles/*.lock

.travis.yml

@@ -1,8 +1,14 @@
 language: ruby
 sudo: false
 cache: bundler
+before_script: bundle install --jobs=3 --retry=3
 
 rvm:
-- 2.2.7
-- 2.3.4
-- 2.4.1
+  - 2.2.7
+  - 2.3.4
+  - 2.4.1
+
+gemfile:
+  - gemfiles/Gemfile.rails-4-2stable
+  - gemfiles/Gemfile.rails-5-0stable
+  - gemfiles/Gemfile.rails-5-1stable

gemfiles/Gemfile.rails-4.2-stable

@@ -0,0 +1,11 @@
+source "https://rubygems.org"
+
+gemspec path: ".."
+
+gem "rails", github: "rails/rails", branch: "4-2-stable"
+
+group :test do
+  gem 'capybara', '>= 2.1'
+  gem 'poltergeist', '~> 1.5'
+  gem 'sqlite'
+end

gemfiles/Gemfile.rails-5-0-stable

@@ -0,0 +1,11 @@
+source "https://rubygems.org"
+
+gemspec path: ".."
+
+gem "rails", github: "rails/rails", branch: "5-0-stable"
+
+group :test do
+  gem 'capybara', '>= 2.1'
+  gem 'poltergeist', '~> 1.5'
+  gem 'sqlite'
+end

gemfiles/Gemfile.rails-5-1-stable

@@ -0,0 +1,11 @@
+source "https://rubygems.org"
+
+gemspec path: ".."
+
+gem "rails", github: "rails/rails", branch: "5-1-stable"
+
+group :test do
+  gem 'capybara', '>= 2.1'
+  gem 'poltergeist', '~> 1.5'
+  gem 'sqlite'
+end

pdfjs_viewer-rails.gemspec

@@ -19,6 +19,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency "rails", "> 4.2.0"
   s.add_dependency "sass-rails", "~> 5.0"
+  s.add_dependency "json", "> 1.8.4"
 
   s.add_development_dependency "sqlite3"
 end