You need a repo (on Github).
The name is important as it should be something with homebew- as a prefix. That way it is super easy to add via the brew tap
command.
Put the formulas you want to be in your tap into the root of your repo.
It may be username/homebrew-tap
Add your tap to brew:
$ brew tap username/tap
Now you can install using the formulas you added:
$ brew install yourformulahere
http://formalfriday.club/2015/01/05/creating-your-own-homebrew-tap-and-formula.html