rendering HTML

require "sinatra"

get "/" do
  "<h1>Welcome to the <em>homepage</em></h1>"
end

get "/sinatra" do
  "<h3>I love <a href='http://www.sinatrarb.com/'>Sinatra!</a></h3>"
end

get "/square/:num" do
  num = params[:num].to_i
  num * num
end

b

require "sinatra"

get "/cat" do
   send_file "cat.html"
end