List three latest articles on index

src/task.ml

@@ -99,4 +99,11 @@ let generate_contact target =
 
 let generate_index target =
   let* articles = articles in
+  let rec take n xs =
+    match n, xs with
+    | 0, _ | _, [] -> []
+    | _, x :: xs -> x :: take (pred n) xs
+  in
+  let open Build in
+  let articles = articles >>^ take 3 in
   with_layout (module Model.Articles) articles "pages/index.md" (index_html target)