Merge pull request #1 from lamberta/master

Add directory for tutorials.

Author: lamberta

site/en/tutorials/README.md

@@ -0,0 +1,6 @@
+Add tutorials and notebooks here.
+
+Tutorials are presented in collections, but refrain from adding numbers to the
+filename so we can move things around if needed. Notebooks are docs, docs are
+notebooks. The filename is the URL. Let's use the format:
+`/tutorials/collection-name/an-example-model.ipynb`