Add TODO for mariadb

roles/mariadb/tasks/main.yml

@@ -21,6 +21,8 @@
   notify: Start mysqld service
 
 - name: Secure the installation
+  # TODO: This won't work because it is interactive.
+  # https://stackoverflow.com/questions/25136498/ansible-answers-to-mysql-secure-installation#25140114
   become: true
   command: mysql_secure_installation
   when: "'table already exists!' not in result.stdout"