Support belongs to with namespaced classes

[matthewmcgarvey]

Fixes #684

add_belongs_to namespaced_assoc : Namespaced::Assoc, on_delete: :cascade

Before: namespaced::assocs
After: namespaced_assocs

[jwoertink]

If you have a custom table set within the namespace, does this account for that?

For example:

module Burns
  class Video < BaseModel
    table :videos do

    end
  end
end

# This should still be video_id, not burns_video_is
add_belongs_to video : Burns::Video

[matthewmcgarvey]

@jwoertink I pointed out in the issue, any reference to a class is completely fake in migrations. There is no connection between the name of the class I put in an add_belongs_to and any class in the models directory. That's why the solution I used to get around the bug was to make that type NamespacedAssoc so it got turned into the correct table name. In order to handle what you defined, you'd have to do:

add_belongs_to video : Video, on_delete: :cascade

[jwoertink]

Wait, so you can do add_belongs_to thing : SomeModelThatIsNonExistant, and that will work? 🤨 That sounds like a bug, but I guess irrelevant to this PR.

[matthewmcgarvey]

@jwoertink This is why I don't like using table_for and things like that in migrations. It creates a false impression that the migration is connected to the model when it isn't.