Rails : How to compare (diff) to ActiveRecord models

gistfile1.txt

# Hash.diff is deprecated in Rails 5
# this method does not handle deep hashes (it could be made by recursion though)

class MyModel < ApplicationRecord
  def diff(contract)
    differences = {}
    self.attributes.each do |k,v|
      if contract[k] != v
        differences[k] = {v => contract[k]}
      end
    end
    return differences
  end
end