Adding .gitignore.

Change-Id: Id89a3c470a441c0a3f0885c9b08c15084ef413a1
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..53191fd
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/.v23