Added CI.

Description:
- Added CI configuration.

Signed-off-by: Pavel Kirilin <win10@list.ru>

.gitlab-ci.yaml

+variables:
+  APP_DIR: "/home/jupyter/hub/repo"
+
+stages:
+  - test
+  - cleanup
+
+test:
+  stage: test
+  tags:
+    - private
+  script:
+    - make test
+
+cleanup:
+  stage: cleanup
+  tags:
+    - private
+  script:
+    - make clean
+    - make clean_test
\ No newline at end of file