I have an application that has two similar but different objects and I want to store those objects in the same collection. What is the best way to do this? And how can I query this collection?

Today my collections is represented by: 

```
public IMongoCollection<Post> Posts
{
    get
    {
        return _database.GetCollection<Post>("posts");
    }
}

```

And I have this class:

```
public class Post
{
    public string Id { get; set; }
    public string Message { get; set; }
}

public class NewTypePost
{
    public string Id { get; set; }
    public string Image { get; set; }
}

```

So, today I just can save and query using Post class. Now I want to store and retrive the both classes, Post and NewTypePost.

I tried to change the class type from Post to dynamic. But when I did this, I could not query the collections.