Added instructions on updating

README.md

@@ -166,3 +166,59 @@ The app uses [OpenDyslexic](https://opendyslexic.org/), which is available on-li
 It also has the option of rendering in other system fonts, but this can vary depending on your operating system.
 Because these are proprietary fonts, they cannot be made available on-line in the same way as open source ones should your system not have them.
 Some fonts may not display correctly as a result.
+
+## Updating the Installation
+
+If the app is updated, you can update the version on your installation using the following method:
+
+### Navigate to the root folder
+
+This will be the root folder into which you cloned the git repository when you set the app up.
+
+### Stash your local changes
+
+When you update the code, there is a risk the changes you made to your configuration will be overwritten.
+To avoid this, use the following command:
+
+```git stash```
+
+This will stash the changes you made, and we can re-apply the changes once the new code has been downloaded.
+If you do not have any other changes stashed, the index number of these changes should be `0` in a later step.
+If there are other changes, make sure to note what the correct index number for the stashed changes is.
+
+### Take down the Docker containers
+
+We will need to stop the current containers with the following command:
+
+```sudo docker compose down```
+
+This may take a few seconds.
+
+### Pull the updated code
+
+Download the updated code from the Git repository:
+
+```git pull```
+
+This step might fail if you have any un-stashed local changed.
+
+### Re-Apply your local configurations
+
+Because we stashed our local configurations, we can re-apply them once again:
+
+```git stash pop 0```
+
+The index number (`0`) is assuming there were no other changes saved on your git repository.
+If you have a different index number for the relevant changes from the above step, change this accordingly.
+
+### Re-build the docker image
+
+Now that we have the base code downloaded, we just need to update the docker image:
+
+```sudo docker compose build app```
+
+### Re-build the containers
+
+This is the same last step as running the containers in the last step of the installation:
+
+```sudo docker compose up -d```