! [rejected] master -> master (fetch first) error: failed to push some refs to 'https://github.com/GainzFinder/GainzFinder.git' code example

Example 1: ! [rejected] master -> master (fetch first) error: failed to push some refs to '

git init
git add README.md
git add .
git commit -m "first commit"
git remote add origin https://github.com/userName/repoName.git
git push --force origin master

Example 2: ! [rejected] master -> master (fetch first)

git fetch origin master
git merge origin master