API/TOOHUCardAPI/Data/AppDbContext.cs

using System.Collections;
using System.Collections.Generic;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata;
using TOOHUCardAPI.Data.Models;
using TOOHUCardAPI.Data.Models.ModelBuilders;
using TOOHUCardAPI.Data.Seeders;

namespace TOOHUCardAPI.Data
{
    public class AppDbContext : DbContext
    {
        public DbSet<User> Users { get; set; }
        public DbSet<Card> Cards { get; set; }

        private readonly IEnumerable<ISeeder> _seeders = new List<ISeeder>
        {
            new CardSeeder()
        };

        private readonly IEnumerable<IModelBuilder> _modelBuilders = new List<IModelBuilder>
        {
            new CardLevelModelBuilder()
        };

        public AppDbContext(DbContextOptions options) : base(options)
        {
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            foreach (var builder in _modelBuilders)
            {
                builder.BuildModel(modelBuilder);
            }
            foreach (var seeder in _seeders)
            {
                seeder.SeedData(modelBuilder);
            }
        }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            base.OnConfiguring(optionsBuilder);
        }
    }
}