Today when I try to do a multiple relations, I end up with this error.

undefined method `assert_valid_keys'

First I checked on my relations. But everything seems to be okay with it.

This is made me so crazy. I don’t know what is happening here. Finally I found a reason why?

** You shouldn’t put multiple relations on the same line

Before:

belongs_to :user, :expense_report_status

After:

belongs_to :user
belongs_to :expense_report_status

I don’t know why? but I will find out later. Maybe someone can give me a suggestion with this.