redirect with 303 so as not to carry :DELETE method

The 302 redirect causes the HTML method to be preserved and carried across.  So when redirecting from the index, when unliking it will push the user back to the **destroy** action.

Added 303 to redirect to prevent the method sticking.

I know all of this is customisable, it's just not the best default behaviour.  Results in deleting objects when unliking.