doc/tutorial/basics: remove old docs

Change-Id: Ic7db40083fd993393743332985e502e53443ffba
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/3700
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/doc/tutorial/basics/Readme.md b/doc/tutorial/basics/Readme.md
index 44f9f49..1fe53eb 100644
--- a/doc/tutorial/basics/Readme.md
+++ b/doc/tutorial/basics/Readme.md
@@ -1,62 +1,17 @@
-# CUE Tutorial
+# CUE Tour
 
 ## About this tutorial
 
-This tutorial teaches the fundamentals of CUE.
+The files in this directory are used to generate the tour in
+
+    https://cuelang.org/docs/tutorials/tour/
+
+They are kept here to ensure the examples are in sync with the latest update
+of CUE.
+
 To try out the examples in the tutorial you can follow the
 [installation instructions](../../install.md)
 to get a working setup of CUE.
 
 Use the `cue eval` or `cue export` commands to evaluate an example.
 
-[Click here to start](json.md)
-
-## TOC
-
-- [JSON Sugar and other Goodness](json.md)
-  - [Quotes are Optional for Field Names](fieldname.md)
-  - [Commas are Optional after Fields](commas.md)
-  - [Commas are Still Required in Lists](commaslists.md)
-  - [Curly Braces](curly.md)
-  - [Folding of Single-Field Structs](fold.md)
-  - [Folding all Fields](foldany.md)
-  - [Comments](comments.md)
-  - [Number Literals](numberlit.md)
-  - [String Literals](stringlit.md)
-  - ["Raw" Strings](stringraw.md)
-  - [Bytes](bytes.md)
-- References and Visibility
-  - [References and Scopes](scopes.md)
-  - [Accessing Fields](selectors.md)
-  - [Aliases](aliases.md)
-  - [Emit Values](emit.md)
-  - [Hidden Values](hidden.md)
-- Types ~~and~~ are Values
-  - [Duplicate Fields](duplicates.md)
-  - [Bottom / Error](bottom.md)
-  - [Basic Types](types.md)
-  - [Order is Irrelevant](unification.md)
-  - [Disjunctions](disjunctions.md)
-  - [Default Values](defaults.md)
-  - [Disjunctions of Structs](sumstruct.md)
-  - [Numbers](numbers.md)
-  - [Ranges](ranges.md)
-  - [Predefined Ranges](rangedef.md)
-  - [Lists](lists.md)
-  - [Templates](templates.md)
-- [Modules, Packages, and Instances](instances.md)
-  - [Packages](packages.md)
-  - [Imports](imports.md)
-- Expressions
-  - [Operators](operators.md)
-  - [Interpolation](interpolation.md)
-  - [Interpolation of Field Names](interpolfield.md)
-  - [List Comprehensions](listcomp.md)
-  - [Field Comprehensions](fieldcomp.md)
-  - [Conditional Fields](conditional.md)
-  - [Null or Error coalescing](coalesce.md)
-- Cycles
-  - [Reference Cycles](cycle.md)
-  - [Cycles in Fields](cycleref.md)
-  <!-- - Conversions -->
-  <!-- - Functions (simulating) -->