Gilang: Hallo, Surya

Surya: Hi, Gilang. You look so happy.

Gilang: Yes, I just get a good news.

Surya: Let me guess. You got a surprise from your parents?

Gilang: Nope. Keep guessing.

Surya: You got the scholarship?

Gilang: That's my wish, but no. You got it wrong.

Surya: I give up. Just tell me.

Gilang: I submittted my poem to a competition committee in Jakarta last week. I won it! !

Surya: Really? Oh my God. That's so great. Congratulations.

Gilang: Thanks. I appreciate that.

Surya: I don't know you have such a poetic insight.

Gilang: I like to write poem in my spare time.

Surya: I wish you could be a famous poet one day.

Gilang: Thanks. How nice of you to say that. Come on, lunch is on me.

Surya: Wow! Thanks, mate!

"That's so great. Congratulations."

What does this expression mean?