Add Dockerfile and publish image

Closes: https://todo.xenrox.net/~xenrox/ntfy-alertmanager/4

README.md

@@ -4,6 +4,10 @@
 
 A bridge between ntfy and Alertmanager.
 
+## Installation
+
+Simply use go build or the [docker image] with [docker-compose file].
+
 ## Configuration
 
 You can specify the configuration file location with the `--config` flag. By default
@@ -20,7 +24,7 @@ Example:
 
 ```
 # http listen address
-http-address 127.0.0.1:8080
+http-address :8080
 # Log level (either debug, info, warning, error)
 log-level info
 # Optionally protect with HTTP basic authentication
@@ -75,3 +79,5 @@ Report bugs on the [issue tracker].
 [priority]: https://ntfy.sh/docs/publish/#message-priority
 [tags]: https://ntfy.sh/docs/publish/#tags-emojis
 [issue tracker]: https://todo.xenrox.net/~xenrox/ntfy-alertmanager
+[docker image]: https://hub.docker.com/r/xenrox/ntfy-alertmanager
+[docker-compose file]: https://git.xenrox.net/~xenrox/ntfy-alertmanager/tree/master/item/docker/docker-compose.yml

docker/Dockerfile

@@ -0,0 +1,16 @@
+FROM golang:alpine as build
+WORKDIR /app
+ARG VERSION=0.1.0
+
+RUN wget https://git.xenrox.net/~xenrox/ntfy-alertmanager/refs/download/v${VERSION}/ntfy-alertmanager-${VERSION}.tar.gz -O latest.tar.gz && \
+    tar -zxf latest.tar.gz
+RUN cd ntfy-alertmanager-${VERSION} && \
+    go build -o /app/ntfy-alertmanager
+
+
+FROM alpine:latest
+WORKDIR /
+
+COPY --from=build /app/ntfy-alertmanager /ntfy-alertmanager
+
+ENTRYPOINT [ "./ntfy-alertmanager" ]

docker/docker-compose.yml

@@ -0,0 +1,10 @@
+version: "3"
+services:
+  ntfy-alertmanager:
+    image: xenrox/ntfy-alertmanager:latest
+    container_name: ntfy-alertmanager
+    volumes:
+      - ./config:/etc/ntfy-alertmanager/config
+    ports:
+      - 127.0.0.1:8080:8080
+    restart: unless-stopped