Fixes response_validator to handle 3.0 responses and validate against the schema.

JSON::Validator already handles anyOf oneOf schema definitions, so those can be passed in and validation errors are returned properly

test-app/app/controllers/blogs_controller.rb

@@ -15,7 +15,6 @@ class BlogsController < ApplicationController
     # request body definition for 3.0
     blog_params = params.require(:blog).permit(:title, :content, :headline, :text)
 
-
     @blog = Blog.create(blog_params)
     respond_with @blog
   end