Add a toc file for the plugin documentation

At Google this file is required to host the plugin documentation.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I4258408283a2e29bcbca8e32b16fb423fb35afb7

java/Documentation/toc.md

diff --git a/java/Documentation/toc.md b/java/Documentation/toc.md
new file mode 100644
index 0000000..cc5b544
--- /dev/null
+++ b/java/Documentation/toc.md
@@ -0,0 +1,3 @@
+### Contributor Guides
+* [Build](build.html)
+