docs: add railway troubleshooting for host (#11346)

www/apps/book/app/learn/fundamentals/admin/environment-variables/page.mdx

@@ -6,6 +6,12 @@ export const metadata = {
 
 In this chapter, you'll learn how to use environment variables in your admin customizations.
 
+<Note>
+
+To learn how envirnment variables are generally loaded in Medusa based on your application's environment, check out [this chapter](../../environment-variables/page.mdx).
+
+</Note>
+
 ## How to Set Environment Variables
 
 The Medusa Admin is built on top of [Vite](https://vite.dev/). To set an environment variable that you want to use in a widget or UI route, prefix the environment variable with `VITE_`.

www/apps/book/generated/edit-dates.mjs

@@ -116,5 +116,5 @@ export const generatedEditDates = {
   "app/learn/customization/reuse-customizations/page.mdx": "2025-01-22T10:01:57.665Z",
   "app/learn/update/page.mdx": "2025-01-27T08:45:19.030Z",
   "app/learn/fundamentals/module-links/query-context/page.mdx": "2025-02-03T17:04:24.479Z",
-  "app/learn/fundamentals/admin/environment-variables/page.mdx": "2025-02-05T09:05:33.334Z"
+  "app/learn/fundamentals/admin/environment-variables/page.mdx": "2025-02-06T13:29:46.800Z"
 }

www/apps/resources/app/deployment/medusa-application/railway/page.mdx

@@ -399,6 +399,16 @@ To check issues or errors in your deployed Medusa application:
 2. Click on the Deployments tab.
 3. Click on the View Logs button.
 
+### Set Host
+
+If you encounter issues with the Medusa application, try setting a `HOST` environment variable to `0.0.0.0`:
+
+```bash
+HOST=0.0.0.0
+```
+
+Learn more in the [Railway Documentation](https://docs.railway.com/guides/public-networking).
+
 ---
 
 ## Update Deployed Application

www/apps/resources/generated/edit-dates.mjs

@@ -102,7 +102,7 @@ export const generatedEditDates = {
   "app/contribution-guidelines/docs/page.mdx": "2024-12-12T11:06:12.250Z",
   "app/create-medusa-app/page.mdx": "2025-01-16T10:00:25.975Z",
   "app/deployment/admin/vercel/page.mdx": "2024-10-16T08:10:29.377Z",
-  "app/deployment/medusa-application/railway/page.mdx": "2025-02-03T09:51:08.102Z",
+  "app/deployment/medusa-application/railway/page.mdx": "2025-02-06T13:28:24.999Z",
   "app/deployment/storefront/vercel/page.mdx": "2025-01-06T12:19:31.142Z",
   "app/deployment/page.mdx": "2024-11-25T14:31:45.277Z",
   "app/integrations/page.mdx": "2024-12-16T16:46:12.395Z",