Update .gitlab-ci.yml

.gitlab-ci.yml

-image: docker:latest
+image: docker:19.03.1
 services:
-  - docker:dind
+  - docker:19.03.1-dind
+
+before_script:
+  - docker info
+
 build:
   stage: build
   script:
-    - docker build -t test .
\ No newline at end of file
+    - docker build -t my-docker-image .
+    - docker run my-docker-image /script/to/run/tests
\ No newline at end of file