Ignore *.html files in hooks-its/src/main/resources/Documentation

Thereby it gets easier to develop documentation as we can now run
asciidoc without ending up in a dirty tree.

Change-Id: If5f294bfe94d7ffe9fbad98d6da11af0627521eb

hooks-its/src/main/resources/Documentation/.gitignore

diff --git a/hooks-its/src/main/resources/Documentation/.gitignore b/hooks-its/src/main/resources/Documentation/.gitignore
new file mode 100644
index 0000000..2d19fc7
--- /dev/null
+++ b/hooks-its/src/main/resources/Documentation/.gitignore
@@ -0,0 +1 @@
+*.html