docs (readme): add build and deployment details

Author: StephenHulme

README.md

@@ -68,6 +68,25 @@ npm run test:unit
 npm run test:e2e
 ```
 
+## Building
+
+To build the app for production, run:
+
+```shell
+./compile-build.sh release.tar.gz dist
+```
+
+This runs the npm build script and then compiles the build into a tarball, including the revision number.
+
+The build executes in `production` [mode by default](https://vitejs.dev/guide/env-and-mode#modes) and includes environment variables from the `.env.production` file.
+Environment variables not specified in the `.env.production` file will fall back to values in the `.env` file if they exist.
+
+## Deployment
+
+Deployment is handled by the Deployment project, as usual, however it should be noted that context-specific environment variables undergo a string replacement process during deployment. All environment variables with the prefix `REPLACE_` are replaced with the corresponding values in the Deployment project at deployment time using GNU `awk`'s `gsub` function.
+
+As of June 2024, Quanthub is hosted on the SS load balancers.
+
 ## Notes
 
 A predefined list of printers is used for the printer selection dropdown. This list is defined in the file `src/config/printers.json`. Additional printers, such as the logging printer `stub`, can be added to this list by setting the environment variable `VITE_CUSTOM_PRINTERS` to a comma-separated list of printer names, e.g. `VITE_CUSTOM_PRINTERS=stub,printer1,printer2`.