Using gitinore file to hide appsettings.json does not actually hide it

This is a common misunderstanding about the way .gitignore works we all met at some point when working with Git: .gitignore will ignore all files that are not being tracked yet; indeed, files that are already being tracked in your Git repository are not ignored by your .gitignore setup.

To fulfil your need, it would be sufficient to untrack the files that you desire to ignore, i.e. in your case the appsettings.json file. As reported in your question's comments, this has been answered already here. Then, your .gitignore setup will work as you would expect.

Adding an entry to your .gitignore file won't remove any files that have already been added to your repository. You need to remove them manually. For this you can use the rm command:

git rm project/appsettings.json