added forge 1.20.2

minecraft/forge/Dockerfile

@@ -0,0 +1,13 @@
+FROM alpine
+ARG VERSION=1.20.2
+RUN apk update && apk add openjdk17 wget
+RUN mkdir -p /opt/server
+WORKDIR /opt/server
+COPY forge-${VERSION}-installer.jar /opt
+RUN java -jar /opt/forge-${VERSION}-installer.jar --installServer .
+COPY eula.txt .
+RUN adduser -S minecraft minecraft
+RUN chown -R minecraft /opt/server && chown -R root /opt/server/libraries /opt/server/run.sh /opt/server/user_jvm_args.txt
+USER minecraft
+EXPOSE  25565
+ENTRYPOINT [ "/opt/server/run.sh" ]