Adding very basic query parameter example

[Ken-Miura]

I found query parameter is used in some examples (todos and oauth). But those examples don't focus how to handle query parameter (how to use axum::extract::Query), but their respective theme. I think providing very basic query parameter example (like form example for showing how to handle form) might be useful as introduction.

What do you think about it?

[davidpdrsn]

I don't understand what you mean. The example here shows how to use Query https://docs.rs/axum/0.2.3/axum/extract/struct.Query.html. What do you feel you're missing?

[Ken-Miura]

Thank you for answer. I just thought providing example project itself might be useful, not only document. The document provides enough information. Please close discussion.