[Kaleidoscope] Add an initial "Building an ORC JIT" tutorial chapter.

This is a work in progress - the chapter text is incomplete, though
the example code compiles and runs.

Feedback and patches are, as usual, most welcome.

llvm-svn: 270487
diff --git a/llvm/docs/tutorial/index.rst b/llvm/docs/tutorial/index.rst
index dde53ba..08efdee 100644
--- a/llvm/docs/tutorial/index.rst
+++ b/llvm/docs/tutorial/index.rst
@@ -22,6 +22,16 @@
 
    OCamlLangImpl*
 
+Kaleidoscope: Building an ORC-based JIT in LLVM
+===============================================
+
+.. toctree::
+   :titlesonly:
+   :glob:
+   :numbered:
+
+   BuildingAJIT*
+
 External Tutorials
 ==================