Added ENV Vars for the DB Connection to the Docker part

Dockerfile

@@ -10,4 +10,12 @@ RUN dotnet publish -c Release -o /app
 FROM mcr.microsoft.com/dotnet/core/aspnet:3.1 AS final
 WORKDIR /app
 COPY --from=build /app .
+
+## Intruduce all the ENV vars
+ENV DATABASE_HOST null
+ENV DATABASE_PORT 5432
+ENV DATABASE_NAME null
+ENV DATABASE_USER null
+ENV DATABASE_PASSWORD null
+
 ENTRYPOINT ["dotnet", "ScrumTaskboard.dll"]