Adding blog post to not saved draft of a new archive causes exception

[rengert]

How to reproduce:

• Create a new archive page (only create it and give it a name)
• Create a blog post in it

The manager is redirected to the following url:

http://localhost:5311/manager/post/add/BlogPost/00000000-0000-0000-0000-000000000000

I guess the guid should be the guid of the archive page, but the guid does not exists, because the draft is net saved yet.

Exception is:

KeyNotFoundException: No post type found with the id 'BlogPost'
Piranha.Areas.Manager.Services.PostEditService.Create(string postTypeId, Guid blogId)
Piranha.Areas.Manager.Controllers.PostController.Add(string type, Guid blogId)

I would suggest to disable the button and display the message to save the draft first.