Rename WebsiteIndexController to expected WebsiteController

[Error] Assertion failed: The controller named 'website' could not be
found. Make sure that this route exists and has already been entered at
least once. If you are accessing a controller not associated with a
route, make sure the controller class is explicitly defined.
	(anonymous function) (ember.js, line 415)
[Error] Error while loading route: Error
	(anonymous function) (ember.js, line 415)
[Error] TypeError: 'undefined' is not an object (evaluating
'this.controllerFor("website").set') (web_page_template_route.js, line
40)