Merge branch 'patch-1' into 'master'

add link to Using Docker Build CI docs

See merge request !561

docs/executors/kubernetes.md

@@ -129,7 +129,8 @@ concurrent = 4
 
 There are a couple of caveats when using docker in your builds while running on
 a kubernetes cluster. Most of these issues are already discussed in the
-**Using Docker Images** and **Using Docker Build** sections of the gitlab-ci
+[**Using Docker Build**](https://docs.gitlab.com/ce/ci/docker/using_docker_build.html)
+section of the gitlab-ci
 documentation but it is worth it to revisit them here as you might run into
 some slightly different things when running this on your cluster.