[Django]-Unknown command in django core managment

I think you got this error because the folder name in your app should be management, not managment ^_^

In case anyone else is looking for another answer to a similar problem, make sure you added the related app to installed_apps. I had the same issue and after 30 minutes of renaming the files and trying to copy everything right, I realized that I have not yet added my app to the installed app. Therefore Django did not recognize the new management command.