Update Dockerfile

Dockerfile

@@ -2,12 +2,17 @@ FROM mcr.microsoft.com/dotnet/core/sdk:3.1-alpine AS builder
 WORKDIR /src
 
 # Copy csproj and restore as distinct layers
+COPY Messages.Helpers/*.csproj ./Messages.Helpers/
 COPY Messages.Api/*.csproj ./Messages.Api/
+
 WORKDIR /src/Messages.Api
 RUN dotnet restore
 
 # Copy everything else and publish artifacts
-COPY Messages.Api/. .
+COPY Messages.Helpers/. /src/Messages.Helpers/
+COPY Messages.Api/. /src/Messages.Api/
+
+WORKDIR /src/Messages.Api
 RUN dotnet publish --configuration Release --output artifacts
 
 # Build runtime image