for-shaun.md

git checkout good-branch
git branch -D master

Big -D is a blow-everything-away command, make sure this is what you want! You could alternately create a new branch off of the existing master for safe keeping and then delete master.

git checkout -b master

Create a new master based on the current branch and check it out

git branch -d good-branch

Delete the old branch since your master is now the same as that branch

Then, when you push it to a remote, you'll need to --force it to override the master that's there.

git push origin master --force