Add Debian Stretch symlink

Signed-off-by: Michele Calgaro <michele.calgaro@...>

diff --git a/debian/stretch b/debian/stretch
new file mode 120000
index 0000000..20f08b4
--- /dev/null
+++ b/debian/stretch
@@ -0,0 +1 @@
+squeeze
\ No newline at end of file