Add docs for keycloak users-permissions provider (#2048)

* feat: Add docs for keycloak users-permissions provider

* Update docusaurus/docs/dev-docs/plugins/users-permissions.md

* Update docusaurus/docs/dev-docs/plugins/users-permissions.md

* Update docusaurus/docs/dev-docs/plugins/users-permissions.md

---------

Co-authored-by: Pierre Wizla <[email protected]>

Author: derrickmehaffy

docusaurus/docs/dev-docs/plugins/users-permissions.md

@@ -869,6 +869,39 @@ Version 2 is probably the best choice. See their
   - Client ID: `<Your Patreon Client ID>` - as above
   - Client Secret: `<Your Patreon Client Secret>` - as above
 
+</TabItem>
+
+<TabItem title="Keycloak" value="Keycloak">
+
+<h4 id="keycloak">Using ngrok</h4>
+
+Keycloak accepts the `localhost` urls. <br/>
+The use of `ngrok` is not needed.
+
+<h4 id="keycloak-config">Keycloak configuration</h4>
+
+- Visit your Keycloak admin dashboard
+- If you don't already have a realm, you'll want to create one
+- In the Clients section of your realm, create a new client
+- Under the capability config, ensure you set `Client Authentication` to on to ensure you can create a private key
+- Under the access settings, ensure you set the following values:
+  - **Valid redirect URIs**: `http://localhost:1337/api/connect/keycloak/callback` and `http://localhost:1337/api/connect/keycloak`
+  - **Allowed Web Origins**: `http://localhost:3000` and `http://localhost:1337`
+- In the Client Scopes section, ensure you have the `email` and `profile` scopes set to default
+- In the Client Scopes section, ensure you have the `openid` scope set to default, if you don't have this you will need to manually create it in the global Client Scopes
+
+<h4 id="keycloak-strapi-config">Strapi configuration</h4>
+
+- Visit the User Permissions provider settings page <br/> [http://localhost:1337/admin/settings/users-permissions/providers](http://localhost:1337/admin/settings/users-permissions/providers)
+- Click on the **Keycloak** provider
+- Fill the information:
+  - Enable: `ON`
+  - Client ID: `<Your Keycloak Client ID>`
+  - Client Secret: `<Your Keycloak Client Secret>`
+  - Subdomain: `<Your Keycloak realm url>`, example is either `keycloak.example.com/realms/strapitest` or `keycloak.example.com/auth/realms/strapitest` **without the protocol before it**
+  - The redirect URL to your front-end app: `http://localhost:3000/connect/keycloak/redirect`
+  - (Optional) Set the JWKS URL if you have a custom JWKS URL, example is like `https://keycloak.example.com/auth/realms/strapitest/protocol/openid-connect/certs`
+
 </TabItem>
 </Tabs>