Add ruby 2.4 support
Adding ruby 2.4 support including testing matrix (#9) * Add ruby testing matrix (#8) * Add ruby 2.4 support (#8) * Upgrade rubocop to 1.0
Adding ruby 2.4 support including testing matrix (#9) * Add ruby testing matrix (#8) * Add ruby 2.4 support (#8) * Upgrade rubocop to 1.0