docs: auth providers and file size limitations (#743)

* feat: document file size and improve auth providers

* Minor text modifications

---------

Co-authored-by: Flomp <Flomp@users.noreply.github.com>
Co-authored-by: Christian Beutel <>

docs/src/content/docs/run/backend-configuration/adjust-filesize-limits.mdx

@@ -0,0 +1,46 @@
+---
+title: Adjust Filesize Limits
+description: Configure which file sizes are permitted
+redirectFrom:
+  - /run/backend-configuration/#adjust-filelimits
+---
+import { Aside } from '@astrojs/starlight/components';
+
+<span class="-tracking-[0.075em]">wanderer</span> brings several mechanisms which allow limiting the maximum file size of content provided by users.
+Pictures in the users profile, trail highlights and gpx tracks fall under this file size limit.
+
+<Aside> 
+As <span class="-tracking-[0.075em]">wanderer</span> runs parts of the logic in the users browser those limits can only be enforced, when trying to save a ressource.
+This can lead to non-intuitive errors such as: editing and creating a trail, which is too large, is possible - saving it is not.
+</Aside>
+
+### Body Size Limit
+
+The `BODY_SIZE_LIMIT` is a setting for the frontend, which fails requests if their payload is too large with an `500: Payload Too Large` error.
+The standard value for this setting is `512kb`.
+
+To adjust it, configure the `BODY_SIZE_LIMIT` [Environment Variable](../environment-configuration.md) to a value of you liking.
+To disable this limit entirely you can set this variable to `Infinity`.
+
+```sh
+export BODY_SIZE_LIMIT=Infinity
+```
+
+<Aside type="tip">Read more about the limitations and configuration possibilities on the [SvelteKit Reference](https://svelte.dev/docs/kit/adapter-node#Environment-variables-BODY_SIZE_LIMIT).</Aside>
+
+### Backend Filesize Verification
+
+After the file passes the middleware, PocketBase does an additional verification on the file uploaded.
+This verification includes a check for a maximum file size.
+
+If this verification does not pass the request is terminated with a `500: error validation_file_size_limit`
+
+![Pocketbase Filesize](../../../../assets/guides/pocketbase_filesize.png)
+
+To change this behaviour open the PocketBase admin panel and navigate to the designated table.
+Click the gear icon at the top to open the table's settings and select the gear icon in the row you want to change.
+Adjust the `Max File Size` property.
+
+<Aside>
+The maximum file size has to be specified in bytes. The theoretical maximum of a single file attachment is ~8GB as specified by the [pocketbase documentation](https://pocketbase.io/docs/files-handling/)
+</Aside>

docs/src/content/docs/run/backend-configuration/auth-providers.md

@@ -0,0 +1,33 @@
+---
+title: Configure Authentication Providers
+description: Adjust login methods
+redirectFrom:
+  - /run/backend-configuration/#auth-providers
+---
+
+### Create an OAuth app
+
+This step will vary wildly from provider to provider. Please refer to your provider's documentation for the specific steps.
+
+No matter your provider, you will need a redirect URL. This redirect URL must have the following format: `$ORIGIN/login/redirect`. 
+`$ORIGIN` refers to the `ORIGIN` environment variable that defines the public host at which your <span class="-tracking-[0.075em]">wanderer</span> instance can be reached. 
+So for the default installation, the redirect URL is `http://localhost:3000/login/redirect`.
+
+In any case, once you have successfully created your OAuth app you will receive a Client ID and a Client Secret.
+
+### Enable a provider in PocketBase
+![Pocketbase OAuth](../../../../assets/guides/pocketbase_oauth.png)
+
+In the PocketBase admin panel navigate to the `users` table. Click the gear icon at the top to open the table's settings and navigate to `Options`.
+In the tab `OAuth2`, add your provider and fill in the Client ID and Client Secret from the step before and save your changes.
+
+### Disable password authentication
+
+After enabling the neccessary OAuth2 providers for your application you may want to disable the standard local password authentication.
+
+![Pocketbase OAuth](../../../../assets/guides/pocketbase_password.png)
+
+In the PocketBase admin panel navigate to the `users` table.
+Click the gear icon at the top to open the table's settings and navigate to `Options`.
+
+In the tab `Identity/Password`, toggle the switch and save the configuration.

docs/src/content/docs/run/backend-configuration/index.md

@@ -20,8 +20,9 @@ Via the online dashboard, you will now have access with the user "email@example.
 For specific configuration guides see:
 
 - [SMTP settings](./smtp/)
-- [OAuth2 providers](./oauth2/)
+- [Auth providers](./auth-providers/)
 - [Backup server](./backup-server/)
 - [Custom categories](./custom-categories/)
+- [Adjust Filesize Limits](./adjust-filesize-limits/)
 
 To learn more about what you can do in the admin dashboard please refer to PocketBase's [documentation](https://pocketbase.io/docs/).