Add ping endpoint

backend/sync_server/src/server/ping.rs

@@ -0,0 +1,10 @@
+use axum::Json;
+
+use crate::{database::models::PingResponse, errors::SyncServerError};
+
+#[axum::debug_handler]
+pub async fn ping() -> Result<Json<PingResponse>, SyncServerError> {
+    Ok(Json(PingResponse {
+        server_version: env!("CARGO_PKG_VERSION").to_string(),
+    }))
+}