Pull request for "f" utility

I wrote a small utility for running project specific commands and would like to submit the formula for consideration.

Is this an appropriate pull request?

I'm also very happy to maintain it a downstream fork of homebrew with my own formulae, but would like to get good at contributing, so all critiques are welcome. I will fix all bugs/style/errors/etc, even if it doesn't get merged into master.

Thank you!
actually, you can just `bin.install "f"`