Use user.html_url instead of user.url

When using user.url you'll get a link to the API resource of the user (e.g. https://api.github.com/users/rmehner), but as you're showing it in a browser you most likely want the URL to the proper HTML GitHub profile (e.g.: https://github.com/rmehner).
Merge pull request #3 from rmehner/patch-1

Use user.html_url instead of user.url