Add static checks and migration dry-runs to CI

.gitlab-ci.yml

@@ -22,6 +22,15 @@ before_script:
   - ./Utils/setup.sh --prod
   - mysql --version
 
+check:
+  script:
+    - ./Utils/check.sh --all
+
+check-migrations:
+  script:
+    - source venv/bin/activate
+    - ./manage.py makemigrations --dry-run --check
+
 test:
   script:
     - source venv/bin/activate