How to add a file to a gitignore file code example
Example 1: 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"
Example 2: what to add to gitignore
Look at this awesome site!
https://www.toptal.com/developers/gitignore
Generates a gitignore for you, based on the technologies you're using