docs(readme): add config file instructions

Author: bartholomej

README.md

@@ -22,7 +22,30 @@ yarn add svelte-sitemap --dev
 
 ## Usage
 
-### CLI method (recommended)
+### Config file method (recommended)
+
+Create config file `svelte-sitemap.cjs` in the root of your project:
+
+`svelte-sitemap.cjs`
+
+```js
+module.exports = {
+  domain: 'https://www.example.com'
+  // ...more options
+};
+```
+
+Add `svelte-sitemap` as your postbuild script in `package.json` file:
+
+`package.json`
+
+```json
+{
+  "postbuild": "npx svelte-sitemap"
+}
+```
+
+### CLI method (Alternative 1)
 
 Run in your project root folder to see how it works.
 
@@ -35,7 +58,7 @@ yarn svelte-sitemap --domain https://example.com
 
 It scans your routes in `build/` folder and generates `build/sitemap.xml` file
 
-### TypeScript or JavaScript method (optional)
+### TypeScript or JavaScript method (Alternative 2)
 
 Sometimes it can be useful to call the script directly from JavaScript or TypeScript. Of course there is also this option, but in most cases you will need the [CLI method](#cli-method-recommended) as a postbuild hook.
 
@@ -49,13 +72,13 @@ And now you can run your script like this: `node my-script.js`
 
 ## Example
 
-Highly recommended to use as `postbuild` hook in your `package.json`
+Highly recommended to use as `postbuild` hook in your `package.json` with config file `svelte-sitemap.cjs` in your project root.
 
 ```json
 {
   "name": "my-project",
   "scripts": {
-    "postbuild": "npx svelte-sitemap --domain https://mydomain.com"
+    "postbuild": "npx svelte-sitemap"
   }
 }
 ```
@@ -114,6 +137,7 @@ yarn demo
 - svelte-sitemap is workaround for [this official SvelteKit issue](https://github.com/sveltejs/kit/issues/1142)
 - Brand new version is inspired by [Richard's article](https://r-bt.com/learning/sveltekit-sitemap/)
 - Thanks to [@auderer](https://github.com/auderer) because [his issue](https://github.com/bartholomej/svelte-sitemap/issues/1) changed the direction of this library
+- Config files inspired by [next-sitemap](https://github.com/iamvishnusankar/next-sitemap)
 
 ## ⭐️ Show your support
 

src/vars.ts

@@ -5,10 +5,3 @@ export const DOMAIN = 'https://example.com';
 export const OUT_DIR = 'build';
 
 export const CONFIG_FILE = 'svelte-sitemap.cjs';
-
-// export const OPTIONS: Options = {
-//   domain: DOMAIN,
-//   resetTime: false,
-//   debug: false,
-//   changeFreq: 'weekly'
-// };