Steps to clear out the history of a git/github repository

git-clearHistory

-- Delete .git folder from disk
rm -rf .git

-- recreate the repo from the current content only (note old .gitignore is preserved)
git init
git add .
git commit -m "Initial commit"

-- push to the github remote repo ensuring you overwrite history
git remote add origin https://github.com/<username>/<reponame>.git
git push -u --force origin master

Small edit to make it work

i got frustrated for couple hours and i found your post. Many thanks sir. Saved my day.