docs(integrations): add app linking and access control (#445)

Author: Meierschlumpf

docs/management/integrations/img/form-create-integration.png

@@ -25,24 +25,42 @@ Must be at least 1 character long, can be chosen freely.
 ### Url
 This must be the base URL of the application where Homarr should connect to.
 A few examples for this field include:
-- sabnzbd.example.com
-- example.com/sabnzbd
+- http://sabnzbd.example.com
+- https://example.com/sabnzbd
 
 You must not append any path after the base URL. Some examples for incorrect usage:
-- sabnzbd.example.com/settings
-- example.com/sabnzbd/settings
+- http://sabnzbd.example.com/settings
+- https://example.com/sabnzbd/settings
 
 ### Secrets
 An integration may or may not require secrets to function.
 To process to obtain them is usually [documented in the integration pages](/docs/category/integrations).
 Secrets are encrypted using a symmetric encryption and stored in the database.
-To improve security, they will never be passed to the client and requests to the integrations are performed from the host where Hoamrr is running on.
+To improve security, they will never be passed to the client and requests to the integrations are performed from the host where Homarr is running on.
+
+### Linking applications
+
+During the creation of an integration you can choose to add / link an application to the integration.
+If you want to add one, you can simply specify the app url which will be used for opening the application from Homarr.
+The linked application will also be used for any links the integration widget contains.
+If you already have an application created, you can also link it to the integration by selecting it from the dropdown.
+On the edit page you can always change or remove the linked application.
 
 ### Testing and saving integration
 It is not allowed to create an integration without passing the test.
 This is to ensure that you minimize the amount of broken applications on your Homarr instance.
 The test and create button will perform a network request to the application and authenticate if required.
 
+## Managing permissions
+
+On the edit page of an integration, you can manage which users / groups can
+
+- **Select the integration in items:** Allows users to select the integration and showing data on their board.
+- **Interact with the integration:** Allows users to perform actions on the integration, such as pausing a download.
+- **Full control over the integration:** Allows users to modify the integration properties, including the URL and secrets.
+
+![](./img/integration-permissions.png)
+
 ## Troubleshooting connection
 The connection to your integrations can fail due to many factors. Most of the time it should show you the reason why it failed.
 If it doesn't, you can follow these steps to troubleshoot the issue: