Deleted some commented code inside UserIdentity class.
Added client validation for comments.
Added a link to the post for every comment.
Code format.
Updated _comments view.
Updated code comment.
All the users of the website, that are not authenticated can add a comment to a post.

For this a new rule was added inside the CommentController.
Updated GetUrl function inside Comment model. This impacts the _comments file also.
Manage post, manage comments and approve comments is now available only for the demo user.
Customized the management of post by user. The demo user is the only one that can manage Posts (delete, etc..)