Added arm32 Docker build

src/Dockerfile.arm32

@@ -0,0 +1,27 @@
+FROM microsoft/dotnet:2.1-sdk-alpine AS build
+WORKDIR /app
+
+# copy csproj and restore as distinct layers
+COPY nuget.config .
+COPY *.sln .
+COPY HomeAutio.Mqtt.TiVo/*.csproj ./HomeAutio.Mqtt.TiVo/
+RUN dotnet restore
+
+# copy and build everything else
+COPY HomeAutio.Mqtt.TiVo/. ./HomeAutio.Mqtt.TiVo/
+RUN dotnet build -c Release
+
+# publish
+FROM build AS publish
+WORKDIR /app/HomeAutio.Mqtt.TiVo
+RUN dotnet publish -o out
+
+# build runtime image
+FROM microsoft/dotnet:2.1-aspnetcore-runtime-stretch-slim-arm32v7 AS runtime
+WORKDIR /app
+COPY --from=publish /app/HomeAutio.Mqtt.TiVo/out ./
+
+ENV ENVIRONMENT Production
+
+VOLUME ["/app/appsettings.Production.json", "/app/logs"]
+ENTRYPOINT ["dotnet", "HomeAutio.Mqtt.TiVo.dll"]