CI: track missing migrations

.gitlab-ci.yml

@@ -59,3 +59,21 @@ linters:
         key: linters
         paths:
             - vendor/
+
+# Check whether there are some missing migrations.
+migration_checks:
+    stage: test
+    before_script:
+        - mkdir -p vendor/{pip,apt}
+        - apt-get update -q && apt-get -o dir::cache::archives="vendor/apt" install -yqq postgresql-client
+        - cp cof/settings/secret_example.py cof/settings/secret.py
+        - pip install --upgrade -r requirements.txt
+        - python --version
+    script: python manage.py makemigrations --dry-run --check
+    services:
+        # this should not be necessary…
+        - postgres:9.6
+    cache:
+        key: migration_checks
+        paths:
+            - vendor/