title: .net core build error when building docker image missing Newtonsoft.Json
body: <p>I'm trying to build my .net core project onto a docker container but it seems like it can't find Newtonsoft.Json which I thought was included in the asp.net core </p>
  
  <p>Here is my docker file:</p>
  
  <pre><code>FROM microsoft/dotnet:2.1-aspnetcore-runtime AS base
  WORKDIR /app
  EXPOSE 58373
  EXPOSE 44370
  
  FROM microsoft/dotnet:2.1-sdk AS build
  WORKDIR /src
  COPY ["TestCode/TestCode.csproj", "TestCode/"]
  RUN dotnet restore "TestCode/TestCode.csproj"
  COPY . .
  WORKDIR "/src/TestCode"
  RUN dotnet build "TestCode.csproj" -c Release -o /app
  
  FROM build AS publish
  RUN dotnet publish "TestCode.csproj" -c Release -o /app
  
  FROM base AS final
  WORKDIR /app
  COPY --from=publish /app .
  ENTRYPOINT ["dotnet", "TestCode.dll"]
  </code></pre>
  
  <p>I'm getting the following error when trying to build 
  Error       Could not load file or assembly 'Newtonsoft.Json, Version=9.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The system cannot find the file specified. </p>