Use a more reliable website to crawl in tutorial

[james-s-w-clark]

The tutorial uses the homebase site. I think the site layout has changed - for example, there's no body returned for this code in the tutorial:

iex(3)> response = Crawly.fetch("https://www.homebase.co.uk/our-range/tools")
%HTTPoison.Response{
  body: "",

A more reliable alternative might be some options from

• https://www.scrapethissite.com/pages/
• https://webscraper.io/test-sites Thoughts?