webapi, inital schema and routes (get_users)

provides the infrastructure for the webapi including setting up the
server and the routes.

Implements get_users as a test route

koucha/src/bin/webapi/routes/mod.rs

@@ -0,0 +1,35 @@
+use serde::Serialize;
+use serde_json::json;
+use axum::{Json, Router, response::IntoResponse, routing::get};
+use reqwest::StatusCode;
+
+mod get_users;
+
+use crate::AppState;
+
+pub type ApiResult<T> = Result<ApiResponse<T>, ApiError>;
+
+pub struct ApiResponse<T>(pub StatusCode, pub T);
+
+pub struct ApiError {
+  pub status: StatusCode,
+  pub error: &'static str,
+  pub message: String,
+}
+
+pub fn router() -> Router<AppState> {
+  Router::new()
+    .route("/get_users", get(get_users::handler))
+}
+
+impl IntoResponse for ApiError {
+  fn into_response(self) -> axum::response::Response {
+    let body = json!({ "error": self.error, "message": self.message });
+    (self.status, Json(body)).into_response()
+  }
+}
+impl<T: Serialize> IntoResponse for ApiResponse<T> {
+  fn into_response(self) -> axum::response::Response {
+    (self.0, Json(self.1)).into_response()
+  }
+}