Add a test to Ensure not have missing migrations

Author: luzfcb

.travis.yml

@@ -12,6 +12,7 @@ install: pip install -r dev-requirements.txt
 before_script:
   - psql -c 'create database "python.org";' -U postgres
 script:
+  - python manage.py makemigrations --dry-run --check
   - python -Wd -m coverage run manage.py test -v2
   - coverage report -m --fail-under=75
 notifications: