remove custom sign in resolver

Signed-off-by: Himanshu Mishra <himanshu@orkohunter.net>

docs/getting-started/configuration.md

@@ -189,79 +189,7 @@ components: {
  },
 ```
 
-### Add sign-in resolver in the backend
-
-The Auth backend plugin is responsible for assigning a [Backstage User Identity](../auth/identity-resolver.md#backstage-user-identity) when a user signs in. The Backstage User Identity is fundamentally a JSON Web Token which consists of two parts. The `sub` part is your identity and that identifies your user for any purpose within the Backstage ecosystem. It can for example be used as a primary key in a per-user settings backend, or any other similar purpose. The ent is what relates to ownership (the list of entity refs through which you claim ownership). This is achieved by writing a [Sign In Resolver](../auth/identity-resolver.md#sign-in-resolvers) which takes care of assigning the right identity to the user and even reject SignIn attempts from unrecognized email domains.
-
-> Since [v1.1.0](https://github.com/backstage/backstage/releases/tag/v1.1.0-next.3), you must provide an [explicit sign-in resolver](../auth/identity-resolver.md).
-
-For now, let's create a simple Sign In Resolver which uses the first part of the user's email address to assign a Backstage User Identity.
-
-Replace your `packages/backend/src/plugin/auth.ts` file with the following.
-
-> NOTE: Please update `acme.org` below with your actual company domain to allow login requests from email address with that domain.
-
-```tsx
-import {
-  createRouter,
-  providers,
-  defaultAuthProviderFactories,
-} from '@backstage/plugin-auth-backend';
-import { Router } from 'express';
-import { PluginEnvironment } from '../types';
-import {
-  DEFAULT_NAMESPACE,
-  stringifyEntityRef,
-} from '@backstage/catalog-model';
-
-export default async function createPlugin(
-  env: PluginEnvironment,
-): Promise<Router> {
-  return await createRouter({
-    logger: env.logger,
-    config: env.config,
-    database: env.database,
-    discovery: env.discovery,
-    tokenManager: env.tokenManager,
-    providerFactories: {
-      ...defaultAuthProviderFactories,
-      github: providers.github.create({
-        signIn: {
-          resolver: async ({ profile }, ctx) => {
-            if (!profile.email) {
-              throw new Error(
-                'Login failed, user profile does not contain an email',
-              );
-            }
-            // Split the email into the local part and the domain.
-            const [localPart, domain] = profile.email.split('@');
-
-            // Next we verify the email domain. It is recommended to include this
-            // kind of check if you don't look up the user in an external service.
-            if (domain !== 'acme.org') {
-              throw new Error('Login failed, user email domain check failed');
-            }
-
-            // By using `stringifyEntityRef` we ensure that the reference is formatted correctly
-            const userEntityRef = stringifyEntityRef({
-              kind: 'User',
-              name: localPart,
-              namespace: DEFAULT_NAMESPACE,
-            });
-
-            return ctx.issueToken({
-              claims: {
-                sub: userEntityRef,
-                ent: [userEntityRef],
-              },
-            });
-          },
-        },
-      }),
-    },
-  });
-}
-```
+> Note: The default Backstage app comes with a guest Sign In Resolver. This resolver makes all users share a single "guest" identity and is only intended as a minimum requirement to quickly get up and running. You can read more about how [Sign In Resolvers](../auth/identity-resolver.md#sign-in-resolvers) play a role in creating a [Backstage User Identity](../auth/identity-resolver.md#backstage-user-identity) for logged in users.
 
 Restart Backstage from the terminal, by stopping it with `Control-C`, and starting it with `yarn dev` . You should be welcomed by a login prompt!