Add lightweight async ChuSQL Rust driver and blog query support

examples/query.rs

@@ -0,0 +1,16 @@
+use chusql_driver::Client;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let address = std::env::var("CHUSQL_ADDRESS").unwrap_or_else(|_| "127.0.0.1:7777".into());
+    let user = std::env::var("CHUSQL_USER")?;
+    let password = std::env::var("CHUSQL_PASSWORD")?;
+    let sql = std::env::args()
+        .nth(1)
+        .unwrap_or_else(|| "SHOW DATABASES".into());
+    let client = Client::connect(address, &user, &password).await?;
+    let result = client.query(&sql).await?;
+    println!("{:?}", result);
+    client.close().await;
+    Ok(())
+}