docs: updated README.md

Signed-off-by: Neko Ayaka <neko@ayaka.moe>

README.md

@@ -2,6 +2,83 @@
 
 🏭 Fully implemented wrapper for Factorio headless server console as RESTful and gRPC for easier management through APIs
 
+## Usage
+
+### Pull the image
+
+```shell
+docker pull ghcr.io/nekomeowww/factorio-rcon-api
+```
+
+### Setup servers
+
+When bootstraping the server, you need to specify the RCON port and password for the server to listen to with
+
+- `--rcon-port` for the port number
+- `--rcon-password` for the password
+
+The command may look like this:
+
+```shell
+./factorio \
+ --start-server /path/to/saves/my-save.zip \
+ --rcon-port 27015 \
+ --rcon-password 123456
+```
+
+Or on macOS:
+
+```shell
+~/Library/Application\ Support/Steam/steamapps/common/Factorio/factorio.app/Contents/MacOS/factorio \
+ --start-server /path/to/saves/my-save.zip \
+ --rcon-port 27015 \
+ --rcon-password 123456
+```
+
+Once you are ready, go to the next step to start the API server.
+
+### Factorio server ran with Docker
+
+This is kind of hard to make them communicate easily.
+
+We will need to create dedicated network for the containers to communicate with each other.
+
+```shell
+docker network create factorio
+```
+
+Then, obtain the IP address of the Factorio server container.
+
+```shell
+docker container inspect factorio-server --format '{{ .NetworkSettings.Networks.factorio.IPAddress }}'
+```
+
+Then, start the API server with the following command with the IP address obtained:
+
+```shell
+docker run \
+  --rm \
+  -e FACTORIO_RCON_HOST=<factorio-server-ip> \
+  -e FACTORIO_RCON_PORT=27015 \
+  -e FACTORIO_RCON_PASSWORD=123456 \
+  -p 24180:24180 \
+  ghcr.io/nekomeowww/factorio-rcon-api:unstable
+```
+
+### Factorio server not ran with Docker, Factorio RCON API ran with Docker
+
+For running Factorio server and Factorio RCON API in a same server while not having Factorio server in Docker, you can start the API server with the following command:
+
+```shell
+docker run \
+  --rm \
+  -e FACTORIO_RCON_HOST=host.docker.internal \
+  -e FACTORIO_RCON_PORT=27015 \
+  -e FACTORIO_RCON_PASSWORD=123456 \
+  -p 24180:24180 \
+  ghcr.io/nekomeowww/factorio-rcon-api:unstable
+```
+
 ## API
 
 - OpenAPI v2 spec: [v1.swagger.json](https://github.com/nekomeowww/stdserve/blob/main/apis/stdserveapi/v1/v1.swagger.json)