Using EF 8.

Packages:

<PackageReference Include="EFCore.NamingConventions" Version="8.0.3" />
<PackageReference Include="Microsoft.EntityFrameworkCore" Version="8.0.3" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="8.0.3">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
<PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="8.0.2" />

Running

dotnet ef migrations add Initial --project=App.Database 

Results in

Unable to create a ‘DbContext’ of type ”. The exception ‘Object
reference not set to an instance of an object.’ was thrown while
attempting to create an instance. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728