This is sort of a strawman, nobody on the explicit side of the debate wants people to write more boilerplate -- it's about how discoverable the code (and relatedly how many layers of indirection).

  class Person < ApplicationRecord
   belongs_to :company
   has_many :assignments
  end

For example what are the :company and :assignments symbols referring to? Why are they symbols? If they are models it would be better if they were required explicitly and that way I know where they are defined and can go read the code.