Homebrew update & upgrade:
$ brew update
$ brew upgrade
$ brew cleanup
Backup Homebrew directory:
$ sudo mv /usr/local ~/local
Resotre Homebrew directory:
$ sudo mv ~/local /usr/local
Install Command-Line Tools:
$ xcode-select --install
Run Software-update:
$ sudo softwareupdate --install -all
Re-Install Ruby and RubyGems:
$ rbenv uninstall 2.1.3
$ rbenv install 2.1.3
$ rbenv global 2.1.3
$ gem i bundler mechanize pit