use published image in quick start

README.md

@@ -17,8 +17,11 @@ cp config.example.toml config.toml
 # Set a private api_key in config.toml.
 
 mkdir -p data
-USHORT_UID="$(id -u)" USHORT_GID="$(id -g)" \
-  docker compose -f deploy/docker-compose.build.yml up --build -d
+USHORT_CONFIG="$PWD/config.toml" \
+USHORT_DATA="$PWD/data" \
+USHORT_UID="$(id -u)" \
+USHORT_GID="$(id -g)" \
+  docker compose -f deploy/docker-compose.prod.yml up -d
 ```
 
 The example starts ushort at <http://localhost:18082/s/> and stores its SQLite
@@ -28,12 +31,24 @@ Check it and stop it with:
 
 ```bash
 curl http://localhost:18082/s/api/health
-docker compose -f deploy/docker-compose.build.yml down
+docker compose -f deploy/docker-compose.prod.yml down
 ```
 
-For a production server, use the published image through
-`deploy/docker-compose.prod.yml`; it does not build or require a source
-checkout.
+This pulls the published image; it does not compile ushort or require a Rust
+toolchain.
+
+## Build from source instead
+
+To build the current checkout locally, use the alternative build definition:
+
+```bash
+mkdir -p data
+USHORT_UID="$(id -u)" USHORT_GID="$(id -g)" \
+  docker compose -f deploy/docker-compose.build.yml up --build -d
+```
+
+It uses the same root-level `config.toml` and `data/` directory as the quick
+start.
 
 ## Documentation