add gitignire code example

Example 1: git global ignore

#Create your global ignore file like a normal .gitignore
#in your home folder.
git config --global core.excludesfile /path/to/home/.gitignore
#Your git now exclude any file declared in that .gitignore
#It's useful for hide your IDE's folder (.idea, .vscode, ...)

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