Similar or "You might be interested" posts

This is a nice feature of the blog engine to provide set of articles in the end of the post linking to similar/"you might also like" posts.

One way to implement this might be to add 2 extra metadata into post header, in addition to :title, :layout and others:
1. `:id` - an id/alias of the current post, like `:id :clojure-intro` (so, easily memorizable for the blog owner, and used only internally instead of relying on the post file name or title, which might be changed separately from the `:id`)
2. `:similar-posts `, like `:similar-posts [:clojure-intro :value-simplicity]`, etc. So, the author decides himself what other articles related to this one, and which might be interested for the reader as well.

And then update the page template to iterate over `:similar-posts` if it is not empty, to put set of links on the bottom or somewhere else recommending further reading.