Specify the flask app for CI

.gitlab-ci.yml

@@ -4,6 +4,8 @@ stages:
 test:
   stage: test
   image: python:3.10
+  variables:
+    FLASK_APP: hiboo
   before_script:
     - apt-get update
     - apt-get install -y --no-install-recommends python3-dev libxmlsec1 libxmlsec1-dev libpq-dev libmariadb-dev