First implementation of CI

.gitlab-ci.yml

+variables:
+  TEST_DATASET_NAME: "L570745_uv_first10.MS.tar.xz"
+
+before_script:
+  - cd test_data
+  - tar -xvf $(TEST_DATASET_NAME)
+
+after_script:
+  - echo "All done"
+  
+
+test_DPPP_step:
+  stage: test
+  script:
+    - cwltool steps/DPPP.cwl msin=test_data/L570745_SB000_uv_first10.MS