Feat: Add the ability to create a comment to the post

[akhmaos]

I added a link to the most relevant documentation and enabled the ability to add comments to posts.

We can also discuss the accuracy of choosing a key for comments.

For the key, I chose the solution of "author + date + slug". The reasoning behind this is that one post can have a large number of comments, and using only one of the keys such as author/date/slug immediately would not work. If we used only date/slug, then different users cannot write identical comments. Using author/slug allows us to have one post = one comment from a user, and author/date only allows for adding unique comments there.

We could have used key generation, but that would deprive us of the ability to know the key in advance.