Discord.Net/docs/guides/other_libs/samples/DbContextSample.cs

// ApplicationDbContext.cs
using Microsoft.EntityFrameworkCore;

public class ApplicationDbContext : DbContext
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options) : base(options)
    {

    }

    public DbSet<UserEntity> Users { get; set; } = null!;
}

// UserEntity.cs
public class UserEntity
{
    public ulong Id { get; set; }
    public string Name { get; set; }
}