appraise "4.2" do gem "rails", "~> 4.2" end appraise "5.0" do gem "rails", "~> 5.0" gem "sinatra", git: "https://github.com/sinatra/sinatra" end appraise "5.1" do gem "rails", "~> 5.1" gem "sinatra", git: "https://github.com/sinatra/sinatra" end