README.md in telegram-bot-ruby-0.2.5 vs README.md in telegram-bot-ruby-0.2.6

@@ -36,12 +36,12 @@
 
 Telegram::Bot::Client.run(token) do |bot|
   bot.listen do |message|
     case message.text
     when '/start'
-      bot.api.sendMessage(chat_id: message.chat.id, text: "Hello, #{message.from.username}")
+      bot.api.sendMessage(chat_id: message.chat.id, text: "Hello, #{message.from.first_name}")
     when '/stop'
-      bot.api.sendMessage(chat_id: message.chat.id, text: "Bye, #{message.from.username}")
+      bot.api.sendMessage(chat_id: message.chat.id, text: "Bye, #{message.from.first_name}")
     end
   end
 end
 ```