Add gitlab CI script

Change-Id: I485c743d215dfb83c5f69ac6528f516c31f78332
diff --git a/ci/ccache.conf b/ci/ccache.conf
new file mode 100644
index 0000000..95b69c3
--- /dev/null
+++ b/ci/ccache.conf
@@ -0,0 +1,3 @@
+max_size = 5.0G
+sloppiness = include_file_ctime
+hash_dir = false