instance method parse!

# File railties/lib/rails/commands/plugin.rb, line 325
      def parse!(args=ARGV)
        general, sub = split_args(args)
        options.parse!(general)

        command = general.shift
        if command =~ /^(install|remove)$/
          command = Commands.const_get(command.capitalize).new(self)
          command.parse!(sub)
        else
          puts "Unknown command: #{command}" unless command.blank?
          puts options
          exit 1
        end
      end