Add install instruction

README.md

@@ -32,3 +32,52 @@ Build the application for raspberry pi:
 ```sh
 cargo build --target=armv7-unknown-linux-musleabihf
 ```
+
+## Install
+
+Place the build `pi` binary under `/usr/local/bin/spaceapi-dezentrale-pi-client`
+
+```sh
+install -m 755 -o root -g root \
+    target/release/pi \
+    /usr/local/bin/spaceapi-tuerpi
+```
+
+Configure the spaceapi systemd service by placing the service description under `/etc/systemd/system/spaceapi.service`:
+
+```
+[Unit]
+Description=SpaceAPI tuerpi client
+After=network.target
+
+[Service]
+Type=simple
+Restart=always
+EnvironmentFile=/etc/spaceapi-tuerpi.env 
+ExecStart=/usr/local/bin/spaceapi-tuerpi
+
+[Install]
+WantedBy=multi-user.target
+```
+
+Place the environment configuration with URL and API-Key under `/etc/spaceapi-tuerpi.env`:
+
+```
+SPACEAPI_URL=<your SpaceAPI server endpoint>
+API_KEY=<your secret API key>
+```
+
+Ensure the `/etc/spaceapi-tuerpi.env` can be read only by root by executing:
+
+```
+chmod 600 /etc/spaceapi-tuerpi.env
+chown root:root /etc/spaceapi-tuerpi.env
+```
+
+Apply changes to systemd to enable and start the service
+
+```sh
+systemctl daemon-reload
+systemctl enable --now spaceapi
+```
+