Refactor context factory

[WajahatAliAbid]

Added the default configuration files in the form of a helper method, along with the custom file modulemetadata.json and user secrets. Modified the Program.cs to use that secrets as well as refactored the code in VolvoxHeliosContextFactory to use that configuration instead of hard coded one.

[BillChirico]

Should this be Volvox.Helios.Service since that’s where the migrations are?

[WajahatAliAbid]

I moved the VolvoxHeliosContextFactory to Volvox.Helios.Web, since configurationBuilder uses method Directory.GetCurrentDirectory() and since it's .net core application, I figured it'd use the path for Volvox.Helios.Service build directory instead of intended Volvox.Helios.Web.
So it'd be Volvox.Helios.Web in this case.

[WajahatAliAbid]

The migration command will look for the IDesignTimeDbContextFactory and create migrations in specified output directory. We may need to pass argument -o ../Volvox.Helios.Service/Migrations in our migration command to save migrations in the existing folder. And it'll work as intended.

[BillChirico]

Could you test that this applies migrations properly on a new DB and an existing one? If it works as intended then we can move this

[WajahatAliAbid]

Okay got it

[WajahatAliAbid]

Okay so I verified and realized you are right. It should match the assembly migrations are in. Before making the change it was creating complete database from scratch. I made the change you pointed towards and now without any changes it creates empty migration.

public partial class testmigration : Migration
    {
        protected override void Up(MigrationBuilder migrationBuilder)
        {

        }

        protected override void Down(MigrationBuilder migrationBuilder)
        {

        }
    }

So to verify, I made a change in Poll class and generated migration again and it resulted in this

public partial class testmigration2 : Migration
    {
        protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.AddColumn<string>(
                name: "TestMessage",
                table: "Poll",
                maxLength: 300,
                nullable: false,
                defaultValue: "");
        }

        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.DropColumn(
                name: "TestMessage",
                table: "Poll");
        }
    }

which is the expected change.
FYI;
when I use the command

dotnet ef migrations add testmigration -o ../Volvox.Helios.Service/Migrations

it gives the error

Your target project 'Volvox.Helios.Web' doesn't match your migrations assembly 'Volvox.Helios.Service'. Either change your target project or change your migrations assembly.

so I change the command to this (by specifying the project)

dotnet ef migrations add testmigration -o ../Volvox.Helios.Service/Migrations -p ../Volvox.Helios.Service/Volvox.Helios.Service.csproj

it works. I'll update the pull request for the change.