docs: Move link to the new "external tutorials" area.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171154 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/tutorial/index.rst b/docs/tutorial/index.rst
index c2ef3b9..a7e2c4f 100644
--- a/docs/tutorial/index.rst
+++ b/docs/tutorial/index.rst
@@ -30,6 +30,11 @@
    active development at `<https://github.com/Jonathan2251/lbd>`_ (please
    contribute!).
 
+`Howto: Implementing LLVM Integrated Assembler`_
+   A simple guide for how to implement an LLVM integrated assembler for an
+   architecture.
+
+.. _`Howto: Implementing LLVM Integrated Assembler`: http://www.embecosm.com/download/ean10.html
 
 Advanced Topics
 ===============