Update gitlab-ci.yml

.gitlab-ci.yml

@@ -24,8 +24,9 @@ stages:          # List of stages for jobs, and their order of execution
 build-job:       # This job runs in the build stage, which runs first.
   stage: build
   script:
-    - echo "Compiling the code..."
-    - echo "Compile complete."
+    - cmake --preset=ci .
+    - cd build
+    - ninja
 
 unit-test-job:   # This job runs in the test stage.
   stage: test    # It only starts when the job in the build stage completes successfully.