Add gitlab ci workflow to build docker image

Change-Id: Ibdd497d7645a36534542d2896251393eea36248c
diff --git a/.gitignore b/.gitignore
index dbb295d..68f78b2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@
 !/.gitignore
 !/.github
 !/.dockerignore
+!/.gitlab-ci.yml
 target
 tmp
 logs