yml modification

.gitlab-ci.yml

-stages:                          
- - build                                          
-                                 
-maven-build:                     
-  image: maven:3-jdk-8          
-  stage: build                   
-  script: "mvn package -B"       
-  artifacts:                     
-    paths:                       
-      - target/gitlab-ci-demo.jar
\ No newline at end of file
+stages:
+  - build
+
+build-code-job:
+  stage: build
+  script:
+    - echo "Check the ruby version, then build some Ruby project files:"