command :info do |c|
  c.syntax = 'rubychina info [topic]'
  c.summary = 'Get information about a topic by its number'
  c.description = ''

  c.action do |args, options|
    say_error "Missing topic id" and abort unless @number = (Integer(args.first) rescue nil)

    session = get("/topics/#{@number}.json")
    
    describe session
  end
end