Add a 404 page
This should allow us to use analytics to find broken links, too.
--
MOS_MIGRATED_REVID=90262723
diff --git a/site/404.md b/site/404.md
new file mode 100644
index 0000000..6853665
--- /dev/null
+++ b/site/404.md
@@ -0,0 +1,14 @@
+---
+layout: default
+permalink: /404.html
+---
+
+404 - Page not found
+====================
+
+<pre>
+<div>$ bazel build :what-you-were-looking-for</div>
+<div>...............</div>
+<div><b><span style="color: red;">ERROR</span></b>: no such page ':what-you-were-looking-for': BUILD file not found on package path.</div>
+<div><b><span style="color: green;">INFO</span></b>: Elapsed time: 0.567s</div>
+</pre>
