Squashed 'third_party/ceres/' content from commit e51e9b4

Change-Id: I763587619d57e594d3fa158dc3a7fe0b89a1743b
git-subtree-dir: third_party/ceres
git-subtree-split: e51e9b46f6ca88ab8b2266d0e362771db6d98067
diff --git a/docs/source/tutorial.rst b/docs/source/tutorial.rst
new file mode 100644
index 0000000..a3fd212
--- /dev/null
+++ b/docs/source/tutorial.rst
@@ -0,0 +1,11 @@
+.. _chapter-tutorial:
+
+========
+Tutorial
+========
+
+.. toctree::
+   :maxdepth: 3
+
+   nnls_tutorial
+   gradient_tutorial