docs: improvements to deployment guides (#6183)

- Add a new deployment overview page giving a general overview of how a Medusa project is deployed
- Add a new section in all backend deployment guides related to the Medusa admin.
- Add a general deployment guide for the medusa admin.
- Add a general deployment guide for the Next.js starter

www/apps/docs/content/deployments/server/general-guide.md

@@ -1,5 +1,5 @@
 ---
-description: "General steps for all hosting providers."
+description: "General steps for deploying the backend."
 addHowToData: true
 ---
 
@@ -59,13 +59,73 @@ Once you set up your PostgreSQL database, make sure to have the connection URL t
 
 ---
 
-## (Optional) Step 5: Setup Architectural Services
+## (Optional) Step 5: Configure the Admin
+
+If you're using the Medusa Admin plugin, you have two options to deploy it: either with the backend or separately.
+
+### Deploying with the Backend
+
+To deploy the admin with the backend:
+
+1. Your chosen hosting provider and plan must offer at least 2GB of RAM.
+2. Enable the [autoRebuild option](../../admin/configuration.mdx#plugin-options) of the admin plugin:
+
+```js title="medusa-config.js"
+const plugins = [
+  // ...
+  {
+    resolve: "@medusajs/admin",
+    /** @type {import('@medusajs/admin').PluginOptions} */
+    options: {
+      autoRebuild: true,
+      // other options...
+    },
+  },
+]
+```
+
+Alternatively, you can use a GitHub action to build the admin as explained [here](../index.mdx#deploy-admin-through-github-action).
+
+### Deploying Separately
+
+If you choose to deploy the admin separately, disable the admin plugin's [serve option](../../admin/configuration.mdx#plugin-options):
+
+```js title="medusa-config.js"
+const plugins = [
+  // ...
+  {
+    resolve: "@medusajs/admin",
+    /** @type {import('@medusajs/admin').PluginOptions} */
+    options: {
+      // only enable `serve` in development
+      // you may need to add the NODE_ENV variable
+      // manually
+      serve: process.env.NODE_ENV === "development",
+      // other options...
+    },
+  },
+]
+```
+
+This ensures that the admin isn't built or served in production. You can also change `@medusajs/admin` dependency to be a dev dependency in `package.json`.
+
+You can alternatively remove the admin plugin for the plugins array.
+
+:::tip
+
+Refer to the [admin deployment guides on how to deploy the admin separately](../admin/index.mdx).
+
+:::
+
+---
+
+## (Optional) Step 6: Setup Architectural Services
 
 Aside from PostgreSQL, you may be using modules or plugins that require some additional architectural setup. For example, if you’re using the [Redis Events Module](../../development/events/modules/redis.md), you must set up a Redis database and obtain a connection URL to it.
 
 ---
 
-## Step 6: Deploy your Backend
+## Step 7: Deploy your Backend
 
 You can deploy your backend now to your hosting provider. During or after the deployment process, based on your hosting provider, you need to add the following environment variables:
 
@@ -87,12 +147,12 @@ Make sure to also add any other environment variables relevant to your backend.
 
 ---
 
-## Step 7: Test it Out
+## Step 8: Test it Out
 
 After you’ve deployed your backend, you can test it out in different ways:
 
 - Go to `<BACKEND_URL>/health`, where `<BACKEND_URL>` is the URL to your deployed backend. If the deployment was successful, you should see `OK` printed in your browser.
-- If you deployed the admin dashboard, you can go to `<BACKEND_URL>/app` to view the admin dashboard. If you changed the value of the admin plugin’s `path` configuration, make sure to replace `app` with that instead.
+- If you deployed the [admin dashboard with the backend](#deploying-with-the-backend), you can go to `<BACKEND_URL>/app` to view the admin dashboard. If you changed the value of the admin plugin’s `path` configuration, make sure to replace `app` with that instead.
 
 ---
 
@@ -109,4 +169,3 @@ If your hosting provider gives you access to execute commands in your deployed M
 ```bash
 npx medusa user --email admin@medusa-test.com --password supersecret
 ```
-