docs: documentation for changing your configuration repository access token (#256)

README.md

@@ -254,6 +254,8 @@ sh bridgehead uninstall
 
 ## Site-specific configuration
 
+[How to Change Config Access Token](docs/update-access-token.md)
+
 ### HTTPS Access
 
 Even within your internal network, the Bridgehead enforces HTTPS for all services. During the installation, a self-signed, long-lived certificate was created for you. To increase security, you can simply replace the files under `/etc/bridgehead/traefik-tls` with ones from established certification authorities such as [Let's Encrypt](https://letsencrypt.org) or [DFN-AAI](https://www.aai.dfn.de).

docs/update-access-token.md

@@ -0,0 +1,42 @@
+## How to Change Config Access Token
+
+### 1. Generate a New Access Token
+
+1. Go to your Git configuration repository provider, it might be either [git.verbis.dkfz.de](https://git.verbis.dkfz.de) or [gitlab.bbmri-eric.eu](https://gitlab.bbmri-eric.eu).  
+2. Navigate to the configuration repository for your site.  
+3. Go to **Settings → Access Tokens** to check if your Access Token is valid or expired.  
+   - **If expired**, create a new Access Token.  
+4. Configure the new Access Token with the following settings:  
+   - **Expiration date**: One year from today, minus one day.  
+   - **Role**: Developer.  
+   - **Scope**: Only `read_repository`.  
+5. Save the newly generated Access Token in a secure location.  
+
+---
+
+### 2. Replace the Old Access Token
+
+1. Navigate to `/etc/bridgehead` in your system.  
+2. Run the following command to retrieve the current Git remote URL:  
+   ```bash
+   git remote get-url origin
+   ```
+   Example output:  
+   ```
+   https://name40dkfz-heidelberg.de:<old_access_token>@git.verbis.dkfz.de/bbmri-bridgehead-configs/test.git
+   ```
+3. Replace `<old_access_token>` with your new Access Token in the URL.  
+4. Set the updated URL using the following command:  
+   ```bash
+   git remote set-url origin https://name40dkfz-heidelberg.de:<new_access_token>@git.verbis.dkfz.de/bbmri-bridgehead-configs/test.git
+   
+   ```
+
+5. Start the Bridgehead update service by running:  
+   ```bash
+   systemctl start bridgehead-update@<project>
+   ```
+6. View the output to ensure the update process is successful:  
+   ```bash
+   journalctl -u bridgehead-update@<project> -f
+   ```