appraise "rails4.2.x" do gem "railties", "~> 4.2.0" end appraise "rails5.x" do gem "railties", "~> 5.0" end appraise "sinatra1.x" do gem "sinatra", "~> 1.4" end appraise "sinatra2.x" do gem "sinatra", "~> 2.0" end