modify gitignore code example

Example 1: git update gitignore

git rm -r --cached .
git add .
git commit -m "update gitignore"

Example 2: how to create gitignore

# Don't track content of these folders
node_modules/
someOtherfoler/


# Compiled source #
###################
*.com
*.class
*.dll
*.exe
*.o
*.so

*.so

# Packages #
############
# it's better to unpack these files and commit the raw source
# git has its own built in compression methods
*.7z
*.dmg
*.gz
*.iso
*.jar
*.rar
*.tar
*.zip

Example 3: how to git ignore a file

git config --global core.excludesfile ~/.gitignore_global

Example 4: git ignore not saving changes

git rm -rf --cached .
git add .