add link to website in readme
add link to website in readme

Previously the website couldn't be accessed directly from npm and you would have to go to the GitHub's repository first to find the link for the website.
tgriesser/bookshelf,rbong/bookshelf,jadengore/bookshelf,TinOo512/bookshelf,bookshelf/bookshelf,seegno-forks/bookshelf,seegno-forks/bookshelf,tgriesser/bookshelf,jadengore/bookshelf,TinOo512/bookshelf,rbong/bookshelf,jordansexton/bookshelf,jadengore/bookshelf,bookshelf/bookshelf,jordansexton/bookshelf