Lemonade beer help

I had a beer at PF Chang’s the other night, and the waitress said they put ginger, lemon juice, and sugar into some Japanese beer. Long story short, it tasted kinda like a blue moon beer, but fresher with a strong nice crisp lemon flavor.

Now I want to try, and brew something to that effect, any suggestions?
I really have no idea how to get the sugar into the beer after fermentation, short of just mixing it in before severing.
I’ve used lactose to make a sweet black lager, however I don’t think it would be a good fit for this type of beer.

Any help would be much appreciated…

In Austria they mix 50/50 white and lemonaid in a huge mug for lunch!

That’s all they do is add it before serving, much like a “shandy”.