Resolve "Improve gitlab pipelines"

Closes #5 (closed)

.gitlab/server.gitlab-ci.yml

-
-
-test-server:
+server-setup:
   image: python
-  cache:
+  stage: setup
+  artifacts:
     paths:
-      - server/env/
-  stage: server-test
+      - server/env
+    expire_in: 15 min
+    untracked: true
   script:
     - python --version
     - pip install virtualenv
@@ -13,4 +13,13 @@ test-server:
     - python -m venv env
     - source env/bin/activate
     - pip install -r requirements.txt
+
+server-test:
+  image: python
+  stage: test
+  dependencies:
+    - server-setup
+  script:
+    - cd server
+    - source env/bin/activate
     - pytest --cov app tests/