Merge pull request #155 from ramananbalakrishnan/relative_url_authenticate

Use root_url from main_app when redirecting the user in authenticate

Author: kevinhughes27

lib/shopify_app/sessions_controller.rb

@@ -35,7 +35,7 @@ def destroy
 
     def authenticate
       if shop_name = sanitize_shop_param(params)
-        fullpage_redirect_to "/auth/shopify?shop=#{shop_name}"
+        fullpage_redirect_to "#{main_app.root_path}auth/shopify?shop=#{shop_name}"
       else
         redirect_to return_address
       end