Registering resources using add_url_rule() does not automatically prefix urls

[mikeywaites]

In some cases we might wan't to manually mount handlers to urls using the standard functionality provided by the flask Blueprint object.

For example, flask-oauthlib provides a view that handles the OAuth authentication flow. It's a little confusing to the user that the normal url_prefixing that occurs when mounting resources does not occur when using the lower level blueprint methods.

Manually Mounting Views on Resources

oauth_resource = Resource('api_v3.authentiation', __name__, url_prefix='/oauth')
oauth_resource.add_url_rule('/authorization', view_func=authorize, methods=['GET'])

Currently this would result in the authorize func being mounted on the url /authorize and not /v3/oauth/authorize as you might expect.