fix lint errors

app.rb

@@ -432,7 +432,7 @@ get "/chunked/:delay" do
   delay = Float(params[:delay])
   stream do |out|
     30.times do |i|
-      out << jsonify({id: i, message: i % 2 == 0 ? "tick" : "tock"})
+      out << jsonify({id: i, message: (i % 2).zero? ? "tick" : "tock"})
       sleep delay
     end
   end