Feature/take and store orders

This link should carry the current photo's instagram ID. Remember to generate this link correctly with javascript too when paginating.

What you should end up with on the page should look like this:

`<a href="/orders/new?instagram_id=12345" class="purchase">buy print</a>`

Then you'll handle this `instagram_id` in `orders#new` by accessing its value through the `params` hash.