Add tup recipes articles

articles/tup_recipes.md

@@ -0,0 +1,19 @@
+---
+title: Tup recipes
+date: 2019-10-28
+---
+
+As of writing, tup is at version
+[0.7.8](https://github.com/gittup/tup/releases/tag/v0.7.8).
+
+Access root of project
+----------------------
+
+Add `&root = .` in your `Tuprules.tup` at the root of your project.
+You can then reference it with `&(root)` in Tupfiles.
+
+Define default behavior
+-----------------------
+
+You can define default behavior with a `Tupdefault`. `Tupdefault` files in child
+directory take precedence of the one in the parent directory.