add supplier by ID returns NULL

[johnvic]

Hi Steve,

Great package! Very big help for my project. I got an issue with adding supplier by ID,
This line return $this->suppliers()->find($id); under InventoryTrait, it returns NULL. I am quite new to traits. As per description it is the belongs to many relationship. Am I correct?
I changed the code to return Supplier::find($id);, it worked fine. Am missing something?

thank you