git add file to ignore after added code example

Example 1: gitignroe remove folder

git rm -r --cached some-directory
git commit -m 'Remove the now ignored directory "some-directory"'
git push origin master

Example 2: how to put files into gitignore

$ echo debug.log >> .gitignore
$ git rm --cached debug.log
rm 'debug.log'
$ git commit -m "Start ignoring debug.log"