📝 Add a brief document on the built-in api proxy.

Author: hayleigh-dot-dev

gleam.toml

@@ -15,6 +15,7 @@ internal_modules = ["lustre_dev_tools/*"]
 [documentation]
 pages = [
     { title = "Static assets", path = "assets.html", source = "./pages/assets.md" },
+    { title = "Proxying requests", path = "proxying.html", source = "./pages/proxying.md" },
     { title = "TOML reference", path = "toml-reference.html", source = "./pages/toml-reference.md" }
 ]
 

pages/proxying.md

@@ -0,0 +1,27 @@
+# API Proxying
+
+Often you'll be developing your Lustre application alongside a separate backend
+app. This can cause some problems during development as you'll typically run into
+CORS issues when your Lustre app tries to make requests to your backend running
+on a different port.
+
+To solve this, Lustre's development server includes support for proxying API
+requests to another server. This means your application code doesn't require
+environment-specific logic to determine where to send API requests to, instead
+it always hits a path like `/api/users` and the development server takes care of
+proxying that request to your backend.
+
+## Configuration
+
+To configure the API proxy, you'll need to add an entry to your `gleam.toml` file
+under the `tools.lustre.dev` section. The most common configuration looks something
+like this:
+
+```toml
+[tools.lustre.dev]
+proxy = { from = "/api", to = "http://localhost:3000/api" }
+```
+
+In this example, any requests made to paths starting with `/api` will be forwarded
+to `http://localhost:3000/api`. So a request to `/api/users` would be proxied to
+`http://localhost:3000/api/users`.