Added documentation for ArozOS update

documents/How to update ArozOS.md

@@ -0,0 +1,116 @@
+# Updating ArozOS
+
+## Backup Important Files
+
+Before any update of ArozOS, backup the following files. You can find this with these relative path with the ArozOS root. (Default: /home/pi/arozos/)
+
+1. system/ao.db (System Database)
+2. system/storage.json (Storage config)
+3. system/bridge.json (Bridge configs)
+4. system/*.json (Group Storage configs)
+5. ./files (User files, if leave -root as default)
+
+## Update Instructions
+
+### Update ArozOS from image / pre-build binary
+
+If you are using a version of ArozOS that is setup with downloading binary executables, (i.e. Dowloading the exe from the Release page), follow the steps below to update your ArozOS
+
+1. Download the new binary and web.tar.gz file. Unzip the web.tar.gz to a temporary location. 
+2. Backup all your important data and configurations.
+3. Replace the old binary executable, web and system folder with your newly downloaded release
+4. Start up the ArozOS binary to complete the update
+
+
+
+### Update ArozOS Raspberry Pi image
+
+If you are using the offical Raspberry Pi image for ArozOS, you can update the ArozOS by connecting to the terminal of the pi via SSH.
+
+1. Connect your pi using SSH. 
+
+   1. If you are on Windows, download and install Putty and connect to your Pi using your pi IP (e.g. 192.168.0.100)
+   2. If you are using MacOS, open Terminal App and enter ssh pi@{your_rasberry_pi_IP} (e.g. ssh [email protected])
+
+2. Backup your important files.
+
+3. Execute the update.sh
+
+   ```
+   cd ~/
+   ./update.sh
+   ```
+
+4. Restart the ArozOS via systemd
+
+   ```
+   sudo systemctl restart arozos
+   
+   #For older version of ArozOS
+   sudo systemctl restart aroz-online
+   ```
+
+   
+
+### Update ArozOS from source
+
+If you are installing ArozOS from source, you can easily update via git command.
+
+1. Backup all your important files
+
+2. Pull the new source from Github
+
+   1. If you have modified the code, you can pull and merge your change into your system
+
+      ```
+      git pull
+      ```
+
+   2. If you have screwed up your source code, you can hard reset your whole source code to the offical repo
+
+      ```
+      git fetch --all
+      git reset --hard origin/master
+      ```
+
+3. Build the new ArozOS from source
+
+   ```
+   go mod tidy
+   go build
+   ```
+
+4. Restart your ArozOS via systemd
+
+   ```
+   sudo systemctl restart arozos
+   ```
+
+
+
+## Frequently Asked Questions
+
+#### Why I cannot connect to my server after update?
+
+If you have modified start.sh / start.bat, you might want to check if the start.sh is being modified in the update process. If no, check if the new ArozOS is started by using the following a command
+
+```
+sudo systemctl status arozos
+```
+
+to check if the service is running or not.  If it is not working, try restart it  using ``` sudo systemctl restart arozos``` or seek help at our Telegram group.
+
+
+
+#### Why my storage pool settings are gone after update?
+
+This is normal if you are replacing the ArozOS using manual overwrite / hard reset method. Simply restore the system/storage/*.json and system/storage.json files and restart ArozOS to restore the previous settings.
+
+
+
+#### Why I cannot discover my device in Network Neighbourhood after the update?
+
+Network Neighbourhood require SSDP broadcast technology. After the old service stopped, it will take some time for the SSDP broadcasted information to timeout and re-discovered from the network. It usually takes a few hours for all computers in the Local Area Network to the next discovery. 
+
+In the mean time, you can use direct IP method to connect to your host by using IP Scanner / visit your router's DHCP client list.
+