def command(command, options = {}, &block)
command = command.to_s
debug "Registered `#{command}`"
descriptions[command] = @next_description if @next_description
@next_description = nil
flag_descriptions[command].update @next_flags if @next_flags
usage_descriptions[command] = @next_usage if @next_usage
@next_flags = nil
@next_usage = []
commands[command] = Command.new(block)
Array(options[:alias] || options[:aliases]).each do |command_alias|
commands[command_alias.to_s] = commands[command.to_s]
end
end