feat: add docker support for backend

backend/Dockerfile

@@ -0,0 +1,27 @@
+# ---- Build Stage ----
+FROM mcr.microsoft.com/dotnet/sdk:9.0.302-alpine3.22 AS build
+WORKDIR /app
+
+# Copy project file and restore dependencies
+COPY backend.csproj ./
+RUN dotnet restore
+
+# Copy all source files and publish
+COPY . ./
+RUN dotnet publish backend.csproj -c Release -o /app/out
+
+# ---- Runtime Stage ----
+FROM mcr.microsoft.com/dotnet/aspnet:9.0.7-bookworm-slim AS runtime
+WORKDIR /app
+
+# Copy published output from build stage
+COPY --from=build /app/out ./
+
+# Expose the WebSocket port
+EXPOSE 5151
+
+# Bind to all network interfaces on port 5151
+ENV ASPNETCORE_URLS=http://+:5151
+
+# Start the app
+ENTRYPOINT ["dotnet", "backend.dll"]

frontend/data/config.yaml

@@ -97,5 +97,5 @@ color:
   piece-ghost: "#9BFCF0"
 
 online:
-  server-url: "ws://localhost:5085"
+  #server-url: "ws://localhost:5151"
-  #server-url: "ws://localhost:5001"
+  server-url: "wss://api.tetris.onl"