ruby on rails - How do I check belongs_to model attributes in a declarative_authorization file? -

I have to check an alces_tek for permission. A user should only create a blog if he is the owner of the project

Model code

  the user has the blog: The blogs have it: Projects: Projects on the project is_On : Blog related_to: User is an Android blog_many: blogposts belong_to: project and blog post related_to: user arti_to: blog end  

and now related authorization part

  user's_promotion_on [: Blog],: From = & gt; [: Create, New, Edit, Update:] if_attribute: project_user_id = & gt; {User.id} is the end  

if_attribute is a problem, how do I check the respective model? (The above if_attribute codeline does not work because blog is_to in project and user_id project_model)

Thank you in advance :)

Thank you to the creator,

  if_attribute: project = & gt; {: User = & gt; {User}} is