Add .gitignore to ignore __pycache__

Change-Id: Ie8e033af3662b42414bdc16b75ef8738cf1a0919
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..c18dd8d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+__pycache__/