appraise 'rails-3' do
  gem 'rack', '< 2'
  gem 'rails', '3.2.22.2'
end

appraise 'rails-4' do
  gem 'rack', '< 2'
  gem 'rails', '~> 4.2.6'
end

appraise 'rails-5' do
  gem 'rails', '~> 5.0.0'
end
