fix: add basic deno serve section (#442)

Co-authored-by: Bartek Iwańczuk <[email protected]>

runtime/manual/tools/index.md

@@ -16,6 +16,7 @@ Deno features before they are finalized.
 - [formatter (`deno fmt`)](./formatter.md)
 - [linter (`deno lint`)](./linter.md)
 - [repl (`deno repl`)](./repl.md)
+- [server (`deno serve`)](./serve.md)
 - [task runner (`deno task`)](./task_runner.md)
 - [test runner (`deno test`)](../basics/testing/index.md)
 - [vendoring dependencies (`deno vendor`)](./vendor.md)

runtime/manual/tools/serve.md

@@ -0,0 +1,32 @@
+# `deno serve`, declarative way to write servers
+
+In addition to `deno run`, Deno offers a `deno serve` command-line option that
+automatically configures servers based on the exports of your main module.
+
+Here's an example of how you can create a simple HTTP server using the `serve`
+subcommand:
+
+```typescript
+export default {
+  async fetch(request) {
+    return new Response("Hello world!");
+  },
+};
+```
+
+In this example, the `fetch` function is used to handle incoming HTTP requests.
+
+The logic inside the `fetch` function can be customized to handle different
+types of requests and serve content accordingly:
+
+```typescript
+export default {
+  async fetch(request) {
+    if (request.url.startsWith("/json")) {
+      return Response.json({ hello: "world" });
+    }
+
+    return new Response("Hello world!");
+  },
+};
+```

sidebars/runtime.js

@@ -180,6 +180,11 @@ const sidebars = {
           label: "deno run",
           id: "manual/tools/run",
         },
+        {
+          type: "doc",
+          label: "deno serve",
+          id: "manual/tools/serve",
+        },
         {
           type: "doc",
           label: "deno task",