Deny access to new posts page when not logged in.
Only show submit post link if logged in.
Use a method to submit the post.
Enforce post URL uniqueness.
Sort posts by submitted timestamp.
Add edit posts form.
Add basic permission to check the post's owner.
Only allow changing certain fields of posts.
Add basic error reporting.
Actually use the error reporting.
Validate post contents on submission.
Validate post contents when editing.
Add comments collection, pub/sub and fixtures
Create a form to submit comments.
Made a simple pub/sub for comments.
Denormalized the number of comments into the post.
Added basic notifications collection.