Wordpress: how to create a user who writes only in one category?

Question

WordPress

You need to add a user to an existing site with the ability to maintain his own column, but so that he does not get into the work of the rest of the site anywhere. I made a category for him in which he can write. Made the user the role of "Author", that is, he can publish posts himself.
1 — How (using a plugin and editing something) to set the rights so that he can’t edit anything else in the admin panel and see except for his category and the posts he created (now he sees all drafts)?
2 - How to disable him the ability to post outside his category?

Answer 1

Edit the role of this user, the plugin you have already found. And for 2, create a new role, assign this user and put a hook for displaying categories on the page for creating/editing a post.

Answer 2

I found http://wordpress.org/plugins/role-scoper/
and why downvote the question? it is logically written and the problem is not from the category “you have not pressed the power button”