public class Post : EntityBase
{
    public string Author { get; set; }

    public string Title { get; set; }

    public string Content { get; set; }

    public string[] Tags { get; set; }

    public DateTime CreatedAtUtc { get; set; }

    public List<Comment> Comments { get; set; }
}

public class Repository<T> : IRepository<T> where T : EntityBase
{
    private readonly ApplicationDbContext dbContext;

    public Repository(ApplicationDbContext dbContext)
    {
        this.dbContext = dbContext;
    }

    public virtual T GetById(int id)
    {
        return dbContext.Set<T>().Find(id);
    }

    public virtual IEnumerable<T> List()
    {
        return dbContext.Set<T>().AsEnumerable();
    }

    public virtual IEnumerable<T> List(System.Linq.Expressions.Expression<Func<T, bool>> predicate)
    {
        return dbContext.Set<T>().Where(predicate).AsEnumerable();
    }

    public void Insert(T entity)
    {
        dbContext.Set<T>().Add(entity);
        dbContext.SaveChanges();
    }

    public void Update(T entity)
    {
        dbContext.Entry(entity).State = EntityState.Modified;
        dbContext.SaveChanges();
    }

    public void Delete(T entity)
    {
        dbContext.Set<T>().Remove(entity);
        dbContext.SaveChanges();
    }
}