What's the recommand method to add a setting option?

I'm new to misago and now I am tring to add a new captcha method for it.

Adding a new captcha is easy. But I want to know what is the recommanded method.

I can just change front-end code, insert captcha component everywhere I want. But since misago have a captcha module, I want to add a captcha in misago' way.

I find that type of captcha is configured by settings.captcha_type. And this type is read from database which is initialized by 0002_users_settings.py.

So I tried to edit 0002_users_settings.py but problems comes ---- I don't now how to make this change came into effect. I tried restart server and manage.py migrate. But nothing happeded.
The only method I found that could work is to drop database, recreate it, and then migrate. But that's ugly. Because dropping database is impossible under production environment.

So, my question is, what is the recommanded method to add a option in settings page in production environment?