add docker support

QRCodeService/Dockerfile

@@ -0,0 +1,23 @@
+#See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile to build your images for faster debugging.
+
+FROM mcr.microsoft.com/dotnet/aspnet:5.0-buster-slim AS base
+WORKDIR /app
+EXPOSE 80
+
+FROM mcr.microsoft.com/dotnet/sdk:5.0-buster-slim AS build
+WORKDIR /src
+COPY ["QRCodeService/QRCodeService.csproj", "QRCodeService/"]
+COPY ["Domain/Domain.csproj", "Domain/"]
+COPY ["Infrastructure/Infrastructure.csproj", "Infrastructure/"]
+RUN dotnet restore "QRCodeService/QRCodeService.csproj"
+COPY . .
+WORKDIR "/src/QRCodeService"
+RUN dotnet build "QRCodeService.csproj" -c Release -o /app/build
+
+FROM build AS publish
+RUN dotnet publish "QRCodeService.csproj" -c Release -o /app/publish
+
+FROM base AS final
+WORKDIR /app
+COPY --from=publish /app/publish .
+ENTRYPOINT ["dotnet", "QRCodeService.dll"]