Update jenkinsfile adding debug = True

expenses_manager/Jenkinsfile

@@ -5,6 +5,7 @@ pipeline {
         // settings.py demands SECRET_KEY unless DEBUG is exactly "True".
         // A throwaway value lets CI run with DEBUG unset — that is, False, as
         // in production — instead of falling back to the insecure dev key.
+        DEBUG = 'True'
         SECRET_KEY = 'ci-only-value-never-used-in-production'
         DJANGO_SETTINGS_MODULE = 'expenses_manager.settings'
         PYTHONUNBUFFERED = '1'